Practical Mysticism in Islam and Christianity: A Comparative Study of Rabia al-Adawiyya and Catherine of Genoa

Abstract

The mystical experiences in various forms are fundamental to major religious traditions. The idea of “mysticism” brings up the concept of the ineffable mysterium, which is seen as the central theme around which religions are based. The comparative studies of Rabia al-Adawiyya and Catherine of Genoa do not intend, as with phenomenological and essentialist approaches to the study of religion, to only focus on the similarities of the mystics in order to find universal structures and essential meanings. Nor does it seek to concentrate solely on the differences between the mystics as done by constructivist scholars. Instead, the comparative methodology used in this article highlights the similarities and differences between the respective mystics, Rabia and Catherine, and uses these comparisons to draw attention to an example of interreligious spirituality that cuts across religious traditions. To illustrate this point, it helps to compare two mystics: Rabia from the Islamic tradition and Catherine from the Christian tradition. This study is structured in four parts: an introduction to the concept of mystical experiences, a brief overview of the lives of Rabia and Catherine, a comparative analysis of their mystical characteristics, and a discussion of how their experiences can serve as a model for interreligious spirituality and friendship.

1. Introduction

In 1999, I witnessed a scene in which an eighteen-year-old high school student killed his fellow classmate due to their differing religious views. These two students thought they were each other’s enemies because of their religious differences. However, Fethullah Gulen argues that religious differences are not the greatest enemy of society. He believed that the greatest enemies were ignorance, poverty, and disunity (Gruevski 2018). My inspiration for this article comes from the Second Vatican Council, particularly a document entitled Nostra Aetate (In Our Time), which focuses on the relationship of the Church to non-Christian religions. Nostra Aetate, one of the sixteen documents of the Vatican II Council, marks a turning point in Roman Catholic relationships with people of other faith traditions. In 2005, Pope Benedict XVI referred to Nostra Aetate as the Magna Carta of the Catholic Church in terms of Muslim and Christian relations (Pope Benedict and Islam n.d.). In Nostra Aetate, the Church recognizes all people’s common origin and destiny and their search for answers to the ultimate question of life through religion (Pope Paul VI 1965, No. 21). Other documents such as Dignitatis Humanae (Declaration on Religious Freedom), Unitatis Redintegratio (Declaration on Ecumenism), Gaudium et Spes (Pastoral Constitution of the Church in the Modern World), Ad Gentes (To the Nations), and Lumen Gentium (Light of the Nation) called on Catholics to respect religious liberty and to take an active and intelligent part in the dialogue. Lumen Gentium, for example, posits that the Church as a Mystical Body of Christ acknowledges that there are “many elements of sanctification and of truth found outside of its visible structure”, (Pope Paul VI 1964, pp. 8–13) and that “those who have not yet received the Gospel are related in various ways to the people of God” (Pope Paul VI 1964, pp. 8–13, 16). Ad Gentes similarly states that the salvific presence of God and the seeds of the Word are present in non-Christian religions (Pope Paul VI 1966, No. 2.).

Following the Council, Pope Paul VI established a secretariat for non-Christians in 1964, which is now the Pontifical Council for Interreligious Dialogue (PCID). Under John Paul II in 1984, the PCID issued the document Dialogue and Mission, which outlined authentic dialogue “as presence and witness; commitment to social development and human liberation; liturgical life, prayer, and contemplation; interreligious dialogue; proclamation and catechesis” (Pontifical Council for Inter-Religious Dialogue 1984, No. 7). Another document, Dialogue and Proclamation, also issued by PCID, states that the goal of interreligious dialogue is the more profound conversion to the truth for each partner involved in it (Pontifical Council for Inter-Religious Dialogue 1984, p. 49).

Before the declaration in Nostra Aetate, there were initiatives to encourage dialogue among people of different religions. In 1893, the Parliament of the World’s Religions held in Chicago brought together notable religious leaders, the Indian Hindu Swami Vivekananda, who directly called for dialogue among the world religions (Brooke 1992, p. 182). This event triggered a positive explosion of interreligious dialogue worldwide. Following the Parliament of the World Religions in Chicago, the World Council of Churches (WCC) made Dialogue one of its core aims (Brooke 1992, p. 182). While the Parliament of the World’s Religions, the teachings of Vatican II, and the documents issued by the PCID continue to provide theoretical frameworks and pastoral insights to the questions relating to interreligious dialogue and religious diversity, there is no specific step-by-step guidance on how to collaborate with people of other faith traditions. Exploring the interdisciplinary study of Rabia and Catherine can provide a common ground for Christian and Muslim dialogue. Today, this question is essential for many people interested in interreligious spirituality and friendship.

The selection of Rabia and Catherine is primarily based on the availability of sources. Sufficient textual material should be accessible for comparing the life and teachings of the mystics. There are many influential mystics in the history of mysticism, yet few reliable sources exist on their life and teachings. Both Rabia and Catherine now have enough surviving texts to proceed confidently with the current comparative methodology. The clear contrast between the two mystics, along with the availability of sources, supports the choice of Rabia and Catherine as comparative figures. These two individuals are grounded in distinct religious traditions, generations, and languages. Furthermore, one was married while the other was not.

I am particularly interested in Rabia due to her significant place in Sufi spirituality. She lived in the eighth century, during the period that gave rise to Sufi streams of thought, and is considered the very first mystical figure of Islam and one of the greatest. Catherine of Genoa, from a different era and religious background than Rabia, also achieved a similar level of spirituality. What makes Rabia and Catherine’s mystical experiences particularly intriguing is their emphasis on mystical practices rather than the theoretical explanation of mystical concepts and doctrines, which serve as the means to attain mystical heights.

Methodologically, this article is a comparative historical analysis of the mystical experiences of two prominent religious figures, Rabia from the Islamic tradition and Catherine from the Christian tradition. The research is based on existing historical texts and literature, focusing on documented events and experiences of these figures who lived centuries ago. The analysis and conclusions drawn in the article are based solely on secondary data obtained from historical records and scholarly interpretations of those records. Thus, utilizing qualitative and descriptive-analytical methods, the research provides insights into how mystics from Islam and Christianity can provide examples of interreligious spirituality.

Mysticism and Mystical Experience

Mysticism is a prevalent religious experience worldwide, but its definition varies among scholars. Ralph Hood notes that a common assumption of many social scientists is that mysticism is like suicide: difficult to study because of its rarity and the limited ability of social scientists to identify the pre-suicidal person (McNamara 2006, vol. 1, p. 124). Wayne Teasdale describes a mystic as an individual who has achieved complete integration. This person has attained a profound inner freedom that allows them to embrace everything as part of their inner experience. The unified individual is unafraid of differing viewpoints but rather welcomes them (Teasdale 1999, p. 232).

According to William Ralph, mysticism is “The attempt to realize, in thought and feeling, the immanence of the temporal in the eternal, and of the eternal in the temporal” (Inge 1899, p. 5). Bernard McGinn defines mysticism as “an attempt to express a direct consciousness of the presence of God” (McGinn 1991, p. xvi). Another author, Evelyn Underhill, defines mysticism as “the expression of the innate tendency of the human spirit towards complete harmony with transcendental order, regardless of the theological formula under which that order is understood” (Underhill 1961, p. XIV). Mysticism is often attributed to religious experience, but research has shown mystical experiences also could occur in individuals who do not see themselves as belonging to religious tradition and, in some cases, do not even see themselves as spiritual in a wider sense (Bledow 2022, p. 2). This raises the question of whether mysticism is exclusive to religions or whether it transcends religious traditions and settings. Underhill defines a mystic as a person who has, in some way, experienced the divine directly and “realized God as an abiding Fact, a living Presence, and Love; and through this, their entire existence was transformed” (Underhill 1964, p. 12). Some scholars argue that Underhill’s definition of a mystic is narrow because there are different categories of mystical experience.

Sebastian Gäb categorizes mystical experiences as follows: First, mystical experiences are unitive, involving a sense of being one with God, the universe, or nature. In some experiences, all things are perceived as one, while in others, the mystic’s mind lacks the sense of distinction between self and other or subject. Second, mystical experiences are noetic. In other words, they are not merely feelings but also possess cognitive content. Third, mystical experiences have no specific content. They are not perceptions of religious entities, such as visions or hearing of voices. Not all mystical experiences are objectless; some include awareness of external objects. In essence, mystical experiences might best be characterized as a certain kind of altered state of consciousness in which there is a connection with the transcendent. Fourth, mystical experiences have an intense emotional quality. The mystics are washed over with feelings of love, awe, peace, bliss, and joy (Gäb 2021, p. 3). The mystical experiences described above are not exhaustive. Other categories of experience might not identify with the mystical aforementioned experiences. Some argue that mysticism in monotheistic religions assumes shared experiences among monotheistic mystics (Dupré 2012). Hamid Hussain affirms this assertion, stating that each monotheistic religion has its own distinct mystical traditions, but there have been cases of mutual influence among them. For instance, all monotheistic religions have a common foundation in an extensive list of prophets and their life stories described in their respective scriptures (Hussain 2023). Now that we have established the concept of mysticism and mystical experience, the next section of our essay discusses Rabia and Catherine, their backgrounds, and their mystical experiences.

2. Rabia al-Adawiyya and Catherine of Genoa—A Brief Background

2.1. Catherine of Genoa—Background

According to Friedrich von Hügel, Catherine of Genoa was born in Genoa, Italy, in 1447 to the family of Giacopo Fieschi and Francesca di Negro. She was the last of five children. The Giacopo family were of noble background with very distinguished descent. At the age of eight, Catherine developed a deep love for prayer and penance. She spent most of her nights in prayer on a hard wooden floor. Catherine was disgusted by her father’s wealth and the privilege of her noble birth (Von Hügel 1927, vol. 1, pp. 96–98).

At the age of twelve, Catherine received a special communion with the Lord. This experience greatly increased her passion for prayer and heightened her sense of God’s presence. At the age of thirteen, she was willing to devote her entire life to serving God in a convent. However, the General Superior turned down her request, thinking she was underage.1

Catherine lost her father. As was the custom of the Genoese, Catherine’s father willed everything to her oldest brother. Thus, the brother became not only in charge of his father’s possessions but also the sole decision-maker of the family. Catherine was given out for marriage to a wealthy Italian man. Though this decision to marry was against her wish, Catherine obeyed her brother’s and mother’s decision and accepted the marriage with great humility and absolute trust in God’s direction (Von Hügel 1927, vol. 1, p. 96).

In the first five years of her marriage, Catherine experienced devastation and heartbreak. Her husband, Giuliano, was not a faithful Christian. Giuliano and Catherine were polar opposites when it came to their devotion to God. Catherine suffered greatly, and life was inconsolably difficult for her. At this point, Catherine sought solace outside her matrimonial home by engaging in some activities in search of peace. However, in all these enterprises, Catherine could not find peace. The more she prayed, the more she became distressed. Having reached the verge of hopelessness, Catherine went to pray in a church on the vigil of St. Benedict. Lifting her weary eyes up, she prayed: “Pray for me, Oh, St. Benedict, that for three months he (Jesus) may keep me sick in bed” (Von Hügel 1927, vol. 1, p. 104). At this time, Catherine was not only dealing with grief; she was at the point of giving up entirely on life. She became withdrawn and kept to herself, showing no interest in anything.

The day after the feast of St. Benedict, Limbania, Catherine’s sister, who was a nun, encouraged her to go to confession at the convent. Catherine was unwilling and did not see the need to go to confession, but her sister persuaded her, saying, “At least go so that you could obtain the blessing of our confessor, a holy and blessed man”. Catherine went to the confession as her sister suggested. Catherine’s experience at this confession was the turning point in her life. Two things happened at the confessional. First, Catherine was wounded forcibly with the love of God; second, she received a clear revelation of her misery and faults and of the goodness of God. This experience was so powerful that it left Catherine unconscious at the confessional (Von Hügel 1927, vol. 1, p. 116).

The outcome of the confession is Catherine’s complete purification and purging of her entire self. She was granted the gift of divine light, which enabled her to see beyond what an ordinary person could see. Her experience at the confessional left her heart aflame and wounded for the love of God. She always desired a heart that was completely united with God’s will (Marabotto 1989). Catherine returned to her matrimonial home after the confession experience. She spent most of her day alone with God in deep contemplation. The only words Catherine could utter at this time were as follows: “Oh Love! It be that you have called me with so much love and revealed to me at one view, what no tongue can describe?” So great was Catherine’s sense of contrition that she devoted a large portion of her life to doing penance and sacrifice for sins. Benedict J. Groeschel explains that Catherine had a vision of Christ “with the cross upon his shoulder, dripping with blood which she saw was shed wholly for love” (Groeschel 1979, pp. 38–42). This experience had a powerful influence on Catherine and formed the basis for her future mystical experience and charitable work with the poor and the sick.

According to Groeschel, Catherine’s husband took ill and died. He converted and even agreed to a chaste marriage before his death. After her husband’s death, Catherine devoted the rest of her life to the works of charity, serving the sick and the underprivileged. The Lord continued to appear to her in different forms, assuring her of His ever-loving presence. When it was time for Catherine to join the Lord, she died peacefully. Pope Clement X beatified Catherine in 1675, while Pope Clement XII canonized her in 1737 (Groeschel 1979).

2.2. Rabia al-Adawiyya Rabia

Rabia was a Sufi Muslim mystic. She was born in about 717 A.D. in Basra to a low-income family in Iraq. Legend has it that Rabia’s parents died while she was very young, and her siblings were forcefully removed from her at a tender age. As an orphan, Rabia was kidnapped and sold into slavery. In her servitude, she served her master diligently day and night. So grievous was her suffering that she looked forward to a day when she would be freed (Smith 1984, p. 1)2.

During her intense suffering, one day Rabia heard a voice that she believed was God’s voice saying, “Grieve not, for on the day of resurrection, thy rank shall be such that those nearest to God in heaven shall envy thee”. Strengthened by these words, Rabia intensified her spiritual exercises, fasting during the day and spending her nights in prayer.3 Rabia understood prayer not as mere intercession for herself or others but as a union with God. Thus, prayer is a complete devotion to the divine Love. For Rabia, God must be loved for His sake only and not for anything else (Smith 1984)4.

Rabia was a celibate, and the adoption of celibacy, too, was quite alien to orthodox Muslims. At a time when marriage was valued and esteemed by orthodox Muslims, Rabia stood as a sign of contradiction. She rejected all her marriage proposals, stating that marriage is for those who exist only for the pleasures of this world. In her own words: “For me, that is not so, since I have ceased to exist, and I have passed out of self. My life is in my Lord, and I am altogether His” (Smith 1984)5. Marriage in Islam is not only a choice but also a responsibility. Surprisingly, no known work criticizes Rabia for her decision to remain celibate. In defending Rabia’s choice of celibacy, Farid al-Din Attar states that if he is asked, “Why have you included Rabe’a in the rank of men?’ my answer is that the prophet himself said, ‘God does not regard your outward forms …’ Moreover, if it is permissible to derive two-thirds of our religion from A’esha, surely it is permissible to take religious instruction from a handmaid of A’esha” (Aṭṭār 1984, p. 40).

Another virtue that stood out for Rabia was her life of prayer and the practice of poverty. Her prayer life developed through the path of poverty and self-denial. This was obvious in her extreme ascetic life, denouncing everything that had to do with the world in order to commit to the things of the divine fully. Legend has it that Rabia had several opportunities to become rich but chose not to. For example, a story was told about how some visitors brought Rabia gifts, but she wouldn’t accept such gifts because she thought God would take care of her needs. Rabia is the epitome of what it means to rely entirely on divine providence, as expressed in her own words, “shall God who provides for those who revile him, not provide for those who love Him? He does not refuse sustenance to one who speaks unworthily of Him. How should he refuse it to one whose soul is overflowing with love toward Him?” (Smith 1930). Rabia thus continued in her demanding quest for a complete union with the divine.

Rabia lived with the passion and zeal of a true lover who puts God ahead of all things. For Rabia, commitment to God meant turning away from sin and all material attractions. By so doing, one is prepared to empty oneself completely of worldly affairs for the sake of the divine. According to John O’Brien, the most famous prayer that shaped Rabia’s attitude of disinterested love for the divine is expressed as follows: “If I worship You from fear of Hell, burn me in Hell, and if I worship You from the hope of Heaven, exclude me thence, but if I worship You for Your own sake then withhold not from me Your eternal beauty” (O’Brien 2010, p. 84). In the early centuries of Sufism, Smith points out how Rabia’s concept of love transformed Sufis’ fear of God into pure, selfless love. Love of God came to be understood as pure love with no conflicts with beliefs and orthodox interpretations. According to O’Brien, this kind of love excludes any sort of external association. It is a total and disinterested love which moves beyond any desire for recompense. It is a pure love rooted in the soul’s thirst for God (O’Brien 2010, p. 84).

Rabia believed that the way to God must be sought through love, which made her the first among the Sufis to teach the doctrine of the disinterested love of God. Legend again has it that Rabi was seen taking fire in one hand and water in the other and running with great speed. When she was asked the reason for her action, she said: “I am going to set fire to Paradise and quench the fires of Hell so that men may worship God for his own glory alone” (O’Brien 2010, p. 91). By this statement, Rabia implied again that God must be sought not because of the joy of heaven or the fear of hell but for the sake of God himself. Rabia was over eighty years old when she died in AD. 801 (O’Brien 2010, p. 91).

3. Themes Common to the Mystical Experience between Rabia and Catherine

3.1. Love of God as Pure Love

One of the striking commonalities between Catherine and Rabia is the notion of pure love. It is worth noting that despite the differences in religious beliefs, these two mystics have a salient concept about the love of God. Both understand the relationship with God as pure love. They believed that love is the foundation and purpose of all relationships. Thus, God must be approached and worshiped for love alone. Catherine puts it more succinctly, saying the following:

Before God created man, love was pure and simple, free from all taint of self-interest and needing no restraint. And in creating man, God was moved by no other cause except his pure love. In all that he did for him, he had no other motive or object. And as his love allows nothing to prevent it from doing all possible good to its beloved, and attends to nothing which is not necessary to that end, so the love of man should return to God all that it receives from him; and then, having no respect for anything but love, it will fear nothing, because it never seeks its advantage.

(Hügel and Von 1923)

A close evaluation of the life of Rabia and Catherine shows that all their actions were motivated by pure love. We see this example in their fierce love of God, which was made concrete in the service of others. Both mystics discovered that the true wealth in life lies in fervent love for the divine, demonstrated through serving others. These two souls were so driven by their love for God that no force could separate them. Following is how Catherine expressed it:

Genuine and pure love is such force that it cannot be diverted from its object, nor can it see or feel anything else. Hence it is a useless toil to try to make such creatures employ themselves in the things of this world, as regard to them they are as insensible as if there were dead.

(Hügel and Von 1923)

Harvey D. Egan has the following to say about Catherine: “God as pure love, incomprehensible love is the salient feature of Catherine’s mysticism. Egan adds that the ray of burning love so united Catherine to God that nothing could separate her from God from that time on” (Egan 2012). Von Hugel supports Egan’s assertion that Catherine, infused with divine love at some point in her life, was able to contemplate the divine with ardent passion. Catherine lacks the adequate words to explain her love relationship with the divine, as she said the following: “It is impossible to describe this love in words or figures which will, not in comparison with the reality, seems entirely false. This only can be understood, namely, that the human intellect is unable to comprehend it. And to him who seeks to know what it is that I know and feel, I can only reply that it transcends all utterance” (Hügel and Von 1923).

Rabia’s concept of divine love is akin to Catherine’s. Drawing from her Sufi background, Rabia understands a relationship with God as pure love. The notion of disinterested love forms the core of her teaching. We see a reflection of the concept of disinterested love in her famous quote mentioned earlier:

If I worship Thee from fear of Hell,

burn me in hell.

And if I worship Thee in the hope of paradise,

exclude me thence,

but if I worship Thee for Thine own sake,

then withhold not from me

Thine eternal beauty.

(O’Brien 2010, p. 83)

Rabia suggests that spirituality should go beyond the traditional idea of paradise as a place of happiness or a reward for a devout life. Instead, she believes that God should be worshipped from a perspective of pure love. This love should overflow into one’s relationships with others, making them feel unconditionally loved. In a similar tone, William Ralph Inge states the following, “Love is not love when it asks for a reward” (Inge 1899, p. 83). Like Catherine, Rabia argues that love, not fear, should be the basis of worshipping God. Rabia thinks the two veils stopping people from approaching God with pure love are the fear of hell and the fear of losing heaven. If there was no hell or heaven, would people still worship God? The concept that God should be worshipped and loved purely for the sake of love is central to the mystical experiences of Rabia and Catherine of Genoa. St. Francis Xavier is another saint who articulated a similar idea about the concept of pure love as the foundation for a relationship with God. Legend has it that Francis drew his inspiration from Rabia’s thought when he composed the following:

O’ God, I love thee, I love thee

Not out of hope of heaven for me

Nor fearing not to love and be

In the everlasting burning …

Not for heaven’s sake, not to be

Out of hell by loving thee

Not for any gains I see

But just the way that thou didst me

I do love and I will love thee …

(Fremantle 1977, p. 54)

Further, Theresa of Lisieux, one of the modern saints who is also known as The Little Flower, has a notion of pure love that resembles that of Rabia and Catherine when she says the following: “My Jesus, Thou knowest I do not serve Thee for the sake of reward, but solely out of love and desire to win Thee souls” (Fremantle 1977, p. 54). Thus, the ultimate goal of these mystics is a complete love relationship with the divine. This leads us to our next discussion on self-denial and sin.

3.2. Self-Denial and a Deep Sense of Sin

Another point of symmetry between Rabia and Catherine is their deep sense of sin. It is commonplace for mystics to continually soul-search for any sin that could cloud their vision of the divine. John of the Cross, one of the ascetical-mystical geniuses of the fifteenth century who was known for his life of austerity, asserts that mystics become conscious of sin or any stain on their soul because the closer they get to God the more illuminated they become, and the more illuminated they become, the more their sense of guilt heightens; consequently, imperfection becomes transparent. John of the Cross refers to the process by which one’s imperfection becomes transparent, where one stands naked before God, naked alone with the Alone as a “mirror for the beginner” (Fremantle 1977, p. 54). John explains that the moment of standing naked before God is not a time of judgment but a moment that also reveals God’s love and grace, which surpasses all sins (Muto and Muto 1994, p. 33).

Like Rabia and John, every tidbit of Catherine’s action reminds her of her imperfection before the divine. As earlier noted, Catherine developed a sense of guilt from a very tender age, for her sin is unbearable, it is hurtful, and should be avoided. She once cried the following: “Oh Lord, no more world, no more sin”(Egan 2012). One may conclude that the secret of Rabia’s and Catherine’s repulsion for sin is the understanding that sin creates a gap between the beloved and the lover. This gap often causes excruciating pain that is hard to bear. Speaking of this effect, Egan states that “the more deeply one experiences God’s nearness, the more one awakens to one’s sinfulness and creaturely nothingness” (Egan 2012). Egan adds that the consciousness of sin as an obstacle is a stage in the mystical journey toward transforming the union between sin and grace. We see Rabia’s repulsion of sin in her long hours of night prayers and penance when she says the following: “My sorrow is not for the things which make me grieve, but my sorrow is for the sins for which I do not grieve” (Smith 1984, p. 47). Both Rabia and Catherine believe that sin was hurtful to the soul to the highest degree, not because it involved punishment in the hereafter but because it was the cause of separation between the soul and God.

3.3. The Desire for Union with the Divine

At the heart of every mystic is the desire to be wholly united with the divine. Like Catherine, Rabia believes she belongs so utterly to God that she cannot think of any other relationship except her relationship with the divine. This fact was evident in the number of times Rabia refused to get married, stating the following: “My life is in my Lord, and I am altogether His. The marriage contract must be asked for from Him and not from me” (Smith 1984, p. 47). Unlike Rabia, Catherine was married, but at a point before the death of her husband, both agreed to a chaste marriage; that is, even though they were legally married, they chose to become celibate. Both Catherine and Rabia understand perfection as a union with the divine, a union that is so profound that separation between the mystic and the divine would be impossible. According to Egan, most mystics think this union prefigures the beatific vision (Egan 2012).

Like Catherine, Rabia lived every day, longing to be wholly united with the divine. The long hours of prayer and penance are signs of immense longing for an unquenchable love. Like Rabia and Catherine, many mystics yearn and thirst for a union that only the divine could fulfill. We see this passionate yearning for union with the divine in St. Augustine, who wrote the following: “Our hearts are restless, oh Lord until they rest in Thee” (Augustine 1800). The goal of mystics, especially in the monotheistic religious traditions, is to achieve complete union with the divine.

4. Synopsis and Analysis

The mystical experiences of Rabia and Catherine provide insights into the extraordinary spirituality and the pursuit of perfection embedded in Islam and Christian traditions. As discussed earlier, Rabia and Catherine’s mystical experiences share some common elements, such as the desire to know God, asceticism, repulsion for sin, and union with the divine, characterized by self-transformation. The mystical element of love in these two mystics is closely related to the concept of the Christian Gospel of love: “Everyone that loves is born of God and knows God”. (1 John 4:7). Most Christian scholars would agree that Catherine can not ascend the ladder of a love of the divine without the light of wisdom from Jesus. But how did Rabia learn to love God? Can we assume that the same Jesus (or the Spirit of Jesus) who taught Catherine how to love and yearn for the divine also taught and implanted his love and wisdom in Rabia in the seventh century, leading her to become one of the most respected and revered saints among Muslims in Basra?6

Furthermore, Rabia and Catherine constantly yearn to be in the presence of the divine. Were they referring to the same God? Well, there are different answers to these questions among scholars.

The proponents of the Common Core Thesis argue that the two mystics share a fundamental underlying essence. In other words, Rabia and Catherine yearned to be in union with the same God, because mystical experience is similar across religious traditions. Scholars, such as Walter T. Stace, affirm that mystics share a core universal principle worldwide (Stace 1961). Hence, Rabia and Catherine could experience the same reality. Ninian Smart agrees with Stace’s claim that mysticism is an experience of undifferentiated unity (Smart 1965, pp. 75–87). He writes the following: “Phenomenologically, mysticism is everywhere the same” (Smart 1965, p. 91). Other scholars representing this school of thought, such as Aldous Huxley, William James, Evelyn Underhill, and Rudolf Otto, also support Stace’s assertion of mysticism as an undifferentiated philosophia perennis (Katz 2020). To further strengthen the Common Core Thesis argument, Underhill asserts that mystics across religious traditions experience the same ultimate Reality; they have common features: “It is always the same Beatific Vision of a Goodness, Truth, and Beauty which is one, even though we find diverse accounts of experience” (Stoeber 2013, p. 4). Put more succinctly, William James states the following: “In mystic states, we both become one with the Absolute, and we become aware of our oneness. This is the everlasting and triumphant mystical tradition, hardly altered by differences of clime or creed …” (James 2002).

In defense of the Common Core Thesis, some scholars would point to Karl Rahner’s famous argument on anonymous Christians. Rahner states the following: “‘Anonymously Christian’” mysticism may even exist outside of Christianity; that is to say, Christ himself may be working outside of established Christianity to be in touch with mystics (known and unknown) in all parts of the world” (Rahner et al. 1986). Rahner implies that no one can limit the extent of God’s love for the people he created and redeemed with his blood. Rahner writes the following: “In every human being … there is something like an anonymous, unthematic, perhaps repressed, basic experience of being orientated to God, which is constitutive of man in his concrete make-up (of nature and grace), which can be repressed but not destroyed, which is ‘mystical …’” (Rahner et al. 1986). St. Paul makes a similar assertion in his address to the Athenians, “God … is not far from each one of us. For in him we live and move and have our being” (Acts 17:27–28).

Advocates of the Common Core Thesis provide two reasons why the thesis is so important: metaphysical and epistemological. According to Sebastian Gäb, the metaphysical reason is that the Common Core Thesis supports religious pluralism, especially as Hick thought of it. If the Common Core Thesis is true, this is evidence that some form of religious pluralism might be true (Gäb 2021, p. 4). Hick proposes his famous pluralistic hypothesis: that there is a single common reality behind all the world’s major religious traditions, which he calls the Real (Hick 1989). But we encounter the Real only in experiences shaped by our various cultural and religious backgrounds. Our cultural schemes act like a filter preventing us from experiencing the Real in itself. All we have is the Real in its cultural disguises (Hick 1989). In the case of Rabia and Catherine, when they experienced the state of union with a personal God, they encountered the Real—their experiences contradict each other only on the surface. The mutually exclusive predicates ‘personal’ and ‘non-personal’ only apply to the different appearances of the Real, not the Real itself (Gäb 2021, p. 4). In the case of Rabia and Catherine, Hick would argue that both mystics experienced the same fundamental reality, so it is not surprising that they should show at least some identical core properties.

Another important aspect of the Common Core Thesis is its focus on epistemology. Gäb explains that the Common Core Thesis promotes the credibility of religious experience. He states that experience is generally one of the most essential sources of knowledge we have. Also, most of what people know about reality, they know from experience. Given this background, mystical experience should be epistemically relevant too (Gäb 2021, p. 4). While others might try to interpret the report of mystical experience, Hood agrees with James that the authority of mystical experience is only warranted for those who have the experience (McNamara 2006, vol. 1, p. 135).

The concept of the Common Core Thesis is debated among scholars. One of the leading critics is Steven T. Katz. In his work, “Exploring the Nature of Mystical Experience”, he presents three arguments against the Common Core Thesis or pluralism of mystical experience. First, Katz argues that the religious beliefs of the mystic heavily influence mystical experiences. In other words, mystics are shaped by their religious traditions (Katz 2020, p. 245). Similarly, Peter Moore adds that cultural and institutional factors can influence mystical experiences and may impact the mystic’s interpretation and experience (More 1978). Katz argues that it is essential to study the mystical experience itself or the reports of such experiences afterward and the consciousness that the mystic brings to the experience, which partly shapes the mystical experience (Katz 2020, p. 224).

Second, Katz argues that the Common Core Thesis’s assertion that mystical experience is ‘paradoxical and ineffable’ is a logical error (Katz 2020, p. 249). Katz contends that terms such as ‘paradoxical’ and ‘ineffable’ do not inform us about the specific content of an experience or any given ontological situation. Instead, they obscure the experience from investigation and maintain a sense of mystery about whatever ontological reality the terms describe. He argues that these terms do not offer data for comparing the compatibility of different experiences (p. 249).

Third, Katz explains that the object, the content, and the state(s) of being involved in a mystical experience are not the same for every religious tradition (Katz 2020, p. 250). For instance, Buddhists aim to end suffering by getting rid of the self in a world without a God. On the other hand, Jewish mystics believe in a self that exists in a world God created and lovingly cared for. Jewish mystics typically seek the state of devekuth—clinging to God as their ultimate goal (p. 252). Given these different ontological backgrounds, Katz contends that there is no way a ‘no-self’ experience of an empty, peaceful self is the same as an intense, loving, intimate relationship between two substantial selves—God and the mystics (p. 252).

Katz concludes by noting that there is no pure, unmediated experience. Mystical experience, like all experience, is organized by, processed through, and made available to us in determinate epistemological ways. In the case of our two mystics, Rabia and Catherine, Katz would argue that Rabia’s mystical experience was shaped by her belief in Muhammad and Allah. In contrast, Catherine’s mystical experience was shaped by her belief in Jesus and the Trinity. Katz adds that all knowledge, including mystical knowledge, is subject to rules that make it possible for such experience to count as experience. Therefore, Katz emphasizes the importance of recognizing the consciousness that mystics bring into their mystical experience, as it shapes the mystic’s encounter (Katz 2020, p. 245).

The two positions discussed above present succinct arguments for and against a shared mystical experience across religious traditions. However, as Louis Dupré mentioned, how far can these different schools of thought go without completely undermining the concept of an experience with a common name? (Dupré 2012, p. 285). As mentioned earlier, the purpose of this essay is not to defend any school of thought in the study of mysticism. Instead, it aims to highlight the common elements of mystical experiences across religious traditions, which can promote interreligious friendship and human flourishing. Certain scholars contend that there is a significant connection between mysticism and moral behavior (Jones and Gellman 2022). They assert that during mystical experiences, individuals lose their sense of self-ego and selfishness, decreasing their inclination to sin; this makes mystics potential moral examples for others. Louis Dupré explains that mystics have always been a moral exemplar for their religious traditions. This was evident in early Muslim mystics such as Rabia, Junayd, and al-Hallaj, as well as in Christian mystics like St. John of the Cross, Teresa of Avila, and Ignatius of Loyola. They all sought a mystical union with God and served as role models in their respective religious traditions (Dupré 2012, p. 292). Dupré maintains that a strong awareness of the divine presence has inspired all major figures of Islam and Christianity.7 He points out that the core of both religious traditions relies on divine presence, without which they could not have begun or survived. Dupré emphasizes that mysticism in monotheistic religions is not only contemplative in the cognitive sense but also primarily about love. All cases discussed on mysticism in Islam and Christianity have highlighted love as the driving force behind mysticism (Dupré 2012, p. 291). Aelred of Rievaulx points out that mystics are friends with God, friends who passionately love God. However, this love can only become a reality when mystics also love others. Aelred of Rievaulx states the following, “The love of friends (neighbors) is necessary if we are to truly love God” (Aelred of Rievaulx 1974, vol. 5, p. 21).

4.1. Mysticism: The Love of God and Neighbor

There is a tendency to differentiate between the internal experiences of mystics (perfect pure love for God) and their actions (love between humans) in the external world. Wayne Teasdale argues that as mystics reach the peak of their spiritual journey, these two realms of experience (internal and external) become unified, ultimately leading to loving relationships with other humans. He explains that when mystics experience the pure love of God, this love permeates everything they do. There is no longer a separation between inner experience and their daily actions, perfect love for God vs. brotherly love. Everything is transformed by their mystical experience, and their relationship with other humans is redefined by the depth of who they have become (Teasdale 1999, p. 96). Often, people see the perfect pure love of God and brotherly love as separate ideas. Thomas Aquinas says the following: “We distinguish in order to understand their unity. And in the end, we understand that they are one” (Teasdale 1999, p. 97). The quality of love that mystics demonstrate towards others is the natural outcome of their mystical experiences, as Silvija Migles notes, ecstatic love, intimate communion with God, and mystical love towards the neighbor at the same time flow towards the meeting with God (Migles 2021). Migles explains that a mystical union with God draws mystics beyond their natural inclination and reinforces concrete love that is attentive to all the needs of others (Migles 2021).

Bediiizzaman Said Nursi affirms Migles’ assertion, stating that brotherly/sisterly love that arises from a close union with God prepares one to be the most magnanimous brother or sister (Gülen 2004b, vol. 3, p. 272). Gülen explains that according to Said Nursi, mystics who have had the favor of experiencing love and unity with God return to the community so that others may experience what they have experienced during their union with God. In other words, pure love is not pure if it cannot be expressed in the community in which one lives. Put differently, Gülen asserts the following:

Souls which have been able to make contact with eternity through love, exert themselves to implant in all other souls what they received from eternity. They dedicate their lives to this sacred duty, for the sake of which they endure every kind of hardship to the end, and just as they pronounce ‘love’ with their last breath, they also breathe love while being raised on the Day of Judgment.

(Gülen 2004a, vol. 2, p. xiii)

The relationship between the pure love of God and brotherly/sisterly love is closely synergistic. One cannot love one’s brother unless one first experiences the love of God. It is not enough to experience the love of God or become united with Him without expressing that experience in one’s community. This is why a mystic who has achieved integration “accepts not only his community, his own society, his own friends, his own culture, but all humankind” (Teasdale 1999, p. 232). Emphasizing the importance of concretizing mystical love in service of others, Meister Eckhart states the following: “If a man were in an ecstasy, as St Paul was, and knew that some sick man needed him to give him a bit of soup, I should think it far better if you would abandon your ecstasy out of love and show greater love in caring for the other in his need” (Eckhart 1981, p. 60). Echart explains that the essence of mysticism is the love of God and one’s neighbor. “Similarly”, Francis, Midhun J. emphasizes that love is the fundamental law among the mystics: love of oneself, love of God, and love of neighbor. As a result, those who have experienced love cannot hate anyone. This is the challenge of mysticism, and it leads to service (Midhun 2021, p. 177). While the climax of mystical experience is union and relationship with God, it leads to a renewed sense of love and connection to others, ultimately inspiring selfless actions and a life lived for the benefit of others (Migles 2021, p. 143).

4.2. Mysticism: A Common Ground for Interreligious Friendship

According to Migles, mysticism is not selfish or individualistic; it is a call to share the union with God and God’s presence in our life with others, to come out of our selfishness, and to share God’s love with others. That is the essence of mysticism. The highest love is not that love that we receive in an extraordinary way, but the one that we share with our neighbors in everyday life since the love of God cannot be separated from the love of neighbor. Thus, through active love toward a neighbor, one begins to understand God’s love (Migles 2021). Rahner asserts that anyone who lives honestly and quietly serves their neighbor is living what he calls “the mysticism of everyday life” (Egan 2012). Not everyone may be able to experience extraordinary ecstatic contemplation like Rabi and Catherine, but everyone can emulate their commitment to God and their actions of love toward their neighbors.

Love for one God and neighbors are vital principles in Christianity and Islam, which could serve as common ground for promoting interreligious friendship. The following sections will highlight two contemporary figures in Islam and Christianity who have been influential in teaching interreligious friendship and the love of neighbor.

In his encyclical “Fratelli Tutti”, Pope Francis calls for human fraternity and social friendships that transcend religious traditions. He states the following: “Issues of human fraternity and social friendship have always been a concern of mine. I have spoken of them repeatedly and in different settings in recent years. In this Encyclical, I have sought to bring together many of those statements and to situate them in a broader context of reflection” (Francis 2020, p. 5). Pope Francis lamented society’s current disconnection and isolation, which hinder fraternity and social friendship. He states the following: “We are growing ever more distant from one another, while the slow and demanding march towards an increasingly united and just world is suffering a new and dramatic setback” (Francis 2020, p. 16). Quoting Benedict XVI in his Encyclical Caritas in Veritate, he says the following: “As society becomes ever more globalized, it makes us neighbors but does not make us brothers” (Pope Benedict XVI 2009). Benedict XVI and Pope Francis have been concerned about the pervading negative impact of disconnection and social exclusion. Pope Francis points out that ignoring the presence of others is gradually becoming a new normal and that we are facing the “realities of the time of great connectedness, but ever-increasing loneliness and lack of social friendship”. He notes that we cannot afford to be indifferent to others because we are all connected, and “we owe our being to the existence of others”. In this regard, Pope Francis remarks the following:

“Human beings are so made that they cannot live, develop, and find fulfillment except ‘in the sincere gift of self to others.’ Nor can they fully know themselves apart from an encounter with other persons: ‘I communicate effectively with myself only insofar as I communicate with others. ‘No one can experience the true beauty of life without relating to others, without having real faces to love. This is part of the mystery of authentic human existence. ‘Life exists where there is bonding, communion, and Fraternity, and life is stronger than death when it is built on true relationships and bonds of fidelity. On the contrary, there is no life when we claim to be self-sufficient and live as islands: in these attitudes, death prevails”.

(Francis 2020, p. 87)

Further, in Human Fraternity, Pope Francis underscores the indispensable role of fraternity in human relationships. He states the following: “Fraternity is one of the fundamental and universal values that ought to undergird relationships between peoples … We are brothers and sisters!” (Francis and Al-Tayyeb 2019).

Another influential figure in the Islamic tradition who promotes interreligious friendship, and the service of neighbors is Fethullah Gülen.8 Gülen believes that “Love is the most essential element in every being; a most radiant light, a great power that can resist and overcome every force. It elevates every soul that absorbs it …” (Yalcin 2017). In another place, he states the following: “Only those who overflow with love will build the happy and enlightened world of the future”. Gülen believes that love, when expressed through service and friendship, has the power to transform society (Michel 2012, p. 2). Gülen’s vision aims to cultivate tolerant, open-minded, and dedicated individuals to foster peace and interreligious harmony. In his speech at the 1999 Parliament of the World’s Religions in Cape Town, Gülen presented a hopeful vision of interreligious relationships and human fraternity. He says the following:

It is my conviction that in the future years, the new millennium will witness unprecedented religious blooming, and the followers of world religions, such as Muslims, Christians, Jews, Buddhists, Hindus, and others, will walk hand-in-hand to build a promised bright future of the world.

(Gülen 1999, p. 12)

Gülen and the Hizmet Movement9 have advanced Gülen’s vision for a transformed world through service, education, and commitment to understanding people of other faith traditions.10

Pope Francis and Gülen exemplify God’s love through consistent advocacy for compassion towards others. Muslims and Christians can use this shared attribute to collaborate in promoting peace and universal love. As the common word between Christians and Muslims states, the future of the world depends on peace between the two groups. The basis for this peace and understanding already exists, as it is fundamental to both faiths: love of the One God and love for one’s neighbor. These principles are repeatedly emphasized in the sacred texts of both Islam and Christianity. Therefore, the unity of God, the importance of love for Him, and the necessity of love for one’s neighbor form the common ground between Islam and Christianity (Malik 2013, p. 204).

5. Conclusions

This essay does not take a position on essentialism or contextualism in the studies of mysticism. Instead, it argues that certain mystical features in Islamic and Christian traditions can enhance human fraternity and social friendships. To establish the truth of my argument, I discuss the general concept of mystical experience. I compare two mystics, Rabia from the Islamic tradition and Catherine from the Christian tradition, providing a brief background of their lives. Furthermore, I compare the common mystical characteristics between Rabia and Catherine, and I explain that some characteristics between these two mystics can provide models of how to promote human fraternity and social friendship. I conclude with Pope Francis’s Encyclical Fratelli Tutti and the works of Fethullah Gülen in which they call for human fraternity and social friendship that transcends geographical barriers, distance, and religious traditions.