I recently attended an interfaith conference in Rome, where an unnamed  Jewish Professor startled the audience by declaring: “I would like to thank the Trinity for preserving Judaism throughout the Middle Ages.” He went on to explain that the dogma of the Trinity, is so foreign to Jewish monotheism, that it strengthened the resilience of embattled Jewish communities, to remain loyal to their faith despite enduring relentless persecution and pressure from the Church to convert.

One of the great blessings of our time is that much of this enmity has been overcome, thanks to profound changes in Christianity’s attitude toward Jews and Judaism. In 2000, during his visit to the Western Wall, Pope John Paul II placed a note in the Kotel expressing a prayer to God and a commitment to “genuine brotherhood with the people of the Covenant.” In a 2015 Church document, The Gifts and the Calling of God Are Irrevocable, it was affirmed that God’s covenant with the Jewish people has never been revoked, that Judaism is not obsolete, and that the Church does not support missionary efforts directed at Jews.

Whereas in the past the survival of the Jewish people often required emphasizing the divisions between Judaism and Christianity, these developments invite a different question: might there now be a basis for cooperation in advancing shared biblical visions? The prophet Zephaniah, for example, envisioned a humanity united in calling upon the name of God and serving Him together. The hope of realizing such a vision within the context of Judaism and its relationship with other religions animates my work at the Ohr Torah Blickle Center for Interfaith Dialogue.

Yet such a vision also requires us to engage seriously with the Christian understanding of God and to reconsider its relationship to Jewish belief, not least by exploring whether, and in what sense, the doctrine of the Trinity can be reconciled with monotheism. Jesus himself, in the Gospel of Mark (12:29), responds to a scribe who asks, “Which commandment is the first of all?” by affirming the essential Jewish creed of the Shema: “Hear, O Israel: the Lord our God, the Lord is One.” The scribe replies, “You are right, Teacher; you have truly said that ‘He is one, and besides Him there is no other.’” Clearly, within Christian self-understanding, the Trinity is not seen as contradicting the oneness of God. But how is this so? And how does this claim relate to the Jewish understanding of the divine and to our core affirmation that God is One?

A Jewish Reading of Christian Theology

It was therefore with great joy and gratitude that I read my mentor, Rabbi Professor Alan Brill’s latest book, A Jewish Trinity: Contemporary Christian Theology through Jewish Eyes (Fortress Press, 2025). Rabbi Brill is uniquely qualified to produce this book: he holds a chair in Jewish–Christian studies at Seton Hall University, a Catholic institution, while possessing deep knowledge of Jewish theology. Most important to me, however, is my trust in his intellectual and theological integrity. When engaging scholars or clerics on sensitive topics beyond my own expertise, I am often concerned that their agendas, or their desire to tell me what I wish to hear may shape their presentation of their tradition. Too often, what is presented as interfaith dialogue risks becoming “interfake.” With Brill I have no such qualms.

Brill’s book goes beyond the doctrine of the Trinity to offer a sustained Jewish engagement with central themes of Christian theology, including the Incarnation, Original Sin, salvation, messianism, and covenant.

Furthermore, the book offers not only a journey into Christian theology, but no less a journey into Jewish theology. Again and again, I found that engaging deeply with Christian ideas allowed me to return to my own tradition with fresh eyes clarifying and sharpening beliefs I had long taken for granted. There is a quiet gift in this kind of encounter: the self-knowledge that emerges through meeting the religious “other.” The Talmud (Berakhot 9b) already gestures toward this, encouraging reflection on the ways on Gentile leaders to later discern those of Jewish leaders.

A striking example for me was in relation to the Christian approach to collective responsibility for Adam’s sin in Eden. The idea that all of humanity bears an inherited guilt, and those human beings lack the capacity to rectify this condition on their own. thus necessitating faith in Jesus and his sacrificial atonement stands in sharp contrast to Jewish thought. The New Testament states: “just as one man’s trespass led to condemnation for all, so one man’s act of righteousness leads to justification and life for all… for just as by the one man’s disobedience the many were made sinners, so by the one man’s obedience the many will be made righteous” (Romans 5:18–19). This highlights the distinctiveness of the Jewish belief in personal responsibility for sin. It is reflected, for example, in the daily prayer, Elohai Neshama, affirming the purity of the soul granted by God, standing in contrast to the notion of a soul tainted by original sin. As Brill cites Rabbi Samson Raphael Hirsch: “every child comes from the hand of God as pure as Adam did; still today every child is born to mankind as pure as an angel.”  And, “Judaism thus constitutes an “emphatic protest” against the doctrine of original sin”.

This chapter also led me to a more painful reflection: the parallel between the idea of collective guilt of all of humanity for Adam’s sin and the historical attribution of collective guilt to the Jewish people for the death of Jesus. This latter doctrine caused immense Jewish suffering in the name of Christianity over the centuries, until it was explicitly rejected by the Catholic Church in Nostra Aetate (1965).

The Jewish emphasis on personal responsibility for sin is inseparable from the belief in humanity’s capacity, and obligation, to repair and transform both the self and the world. This is expressed in the concept of tikkun olam, which operates on both the individual and communal levels. In this view, responsibility is coupled with the ability to achieve atonement and spiritual restoration. This stands in contrast to certain Christian approaches that stress humanity’s inability to achieve salvation independently, and the consequent necessity of divine sacrifice through the death of Jesus.

An important contribution of Brill’s work is his demonstration that, like Judaism, Christianity is not monolithic. It contains diverse voices, ancient and modern, that debate these very doctrines. In this regard, I found especially significant the thought of Pelagius (354–418), who emphasized human freedom and denied original sin. Although Pelagius was condemned in his time, particularly by Augustine, Brill shows that from the Enlightenment onward, various Christian theologians, such as Karl Rahner and Emil Brunner, have revisited these questions, often presenting more positive views of human nature and free will.

Rethinking the Trinity and Monotheism

Returning to the Trinity, Brill makes a crucial point: some of the differences between Judaism and Christianity are not necessarily greater than the differences within each tradition itself. This insight resonates particularly when considering themes of transcendence and immanence within certain strands of Hasidism and Kabbalah, areas in which Brill’s expertise is especially evident.

Brill outlines two fundamental approaches to the Trinity within Christian thought. The first is a model of subordination, in which there exists a hierarchy within the Godhead, with one aspect subordinate to a supreme divine source. The second is modalism, which understands the three as modes or manifestations of a single, undivided God.

In the first approach, the divine elements are distinct and unequal, yet still understood as manifestations of the divine, bearing some resemblance to certain Neoplatonic or Kabbalistic models of emanation. In the second, monotheism is emphasized: the distinctions are not ontological separations but different expressions or “faces” of a single divine reality. This latter view invites comparison to the multiplicity of divine attributes (middot) or names of God in Jewish thought.

According to Brill, the modalist tendency, understanding the three as expressions of one God, became dominant in much of Christian theology. He also brings sources from Saadia Gaon, who regarded Christianity as monotheism, albeit problematic from a Jewish perspective, not because it posits three gods instead of one, but because it compromises divine unity.

Ultimately, we are left with a complex tapestry of both divergence and shared ground between Jewish and Christian beliefs. On the one hand, throughout the ages, Jews and Christians have acknowledged a common faith in a benevolent, transcendent God, the Creator of heaven and earth, who exercises divine providence, rewarding and punishing, alongside many other shared religious tenets. On the other hand, there remain profound disagreements on central theological issues, including the unity of God, the divinity of Jesus, and the doctrine of incarnation.

Where, then, does this leave us, from a Jewish perspective, with regard to the vision of calling together in the name of God? What is the relative significance of that which we share, in light of that which divides us?

Famously, Rabbi Menahem ben Shlomo Meiri (1249–1315) reframed the question of idolatry less as a matter of theology and more as one of ethics. He proposed a fundamental distinction between moral monotheists, among whom he included Jews, Christians, and Muslims, and immoral polytheists. For the Meiri, what ultimately determines the legitimacy of a religion is whether its adherents are “bound by religious morals and laws.”

This approach, I would suggest, is rooted in the Bible’s own explanation for the choosing of Abraham: “For I have singled him out, that he may instruct his children and his posterity to keep the way of the Lord by doing what is just and right” (Genesis 18:19). The essence lies in walking the path of God, a path defined by the pursuit of justice and righteousness. Surely, this can serve as a shared path for Jews and Christians alike.

A striking affirmation of Christian morality appears in the words of Rabbi Yaakov Emden, one of the leading rabbis of the 18th century, who wrote of Christians: “They are careful not to swear falsely and avoid even a hint of theft. They possess desirable character traits and upright morals; the pious among them refrain from revenge, hatred, and causing harm to their enemies” (Leḥem Shamayim, Avot 4:11).

Another significant strand within rabbinic literature is categorizing Christian theology as  shituf,  association of  one overarching God, who is association of an additional divine.  While such theological formulations are prohibited for Jews as a deviation from pure monotheism, they are not forbidden for non-Jews and does not entirely exclude them from the category of monotheistic belief. This distinction reflects a broader idea: Judaism makes more demanding theological claims upon Jews themselves, rooted in the covenant at Sinai. The essence of Judaism is relationship, between people, within community, and with God. Like a marriage covenant, this relationship entails obligations and exclusivity.

From Tolerance to Fraternity

Much of contemporary interfaith discourse emphasizes the value of tolerance. In many contexts, even achieving tolerance would represent meaningful progress. Yet ultimately, the vision for interreligious relations must go beyond tolerance; it cannot be limited to merely enduring one another’s existence.

In Hebrew, the word for tolerance, savlanut, literally means the capacity to bear a burden. While this has its place, it is insufficient as an ideal. What is needed is a deeper paradigm: a relationship grounded in recognizing the value and blessing within the other, their faith, their story, and their identity.

True interfaith engagement cannot remain at the level of polite declarations or superficial affirmations. It must lead us to genuinely perceive the value, legitimacy, and even divine purpose of the other. For genuine fraternity, not mere tolerance, there must be a willingness to understand and truly see the other, including acknowledging real disagreements and divergences. Only such honesty can sustain an authentic relationship.

In this regard, Brill’s book represents a milestone. It offers a serious and nuanced Jewish understanding of Christianity and provides a foundation upon which a future can be built, one in which each tradition remains faithful to its own beliefs, while both recognize that, in meaningful ways, we are brothers and sisters, joined in the calling of God’s name.

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