When Jewish theologian Abraham Joshua Heschel rose to deliver the sole eulogy at Reinhold Niebuhr's funeral in 1971, he captured a remarkable moment of interfaith fellowship that illuminated decades of theological bridge-building between American Jewish and Christian traditions. Selected personally by both Professor and Mrs. Niebuhr, Heschel's tribute - later published in Conservative Judaism - revealed the profound intellectual and spiritual kinship between these influential religious thinkers. Through analysis of the eulogy's rhetorical structure, biblical references, and theological themes, this research explores how Heschel portrayed Niebuhr as a Christian thinker who authentically embodied the Hebrew prophetic tradition while addressing contemporary social and political challenges. The eulogy particularly emphasized Niebuhr's distinctive contribution to American theology through his integration of prophetic traditions within Christian thought and his unwavering commitment to social justice. Beyond commemorating a colleague, Heschel's words marked a significant milestone in American religious history, demonstrating how shared commitments to social justice and spiritual integrity could transcend traditional denominational boundaries.