Constantine’s Sword is a must-read. I first read it in the context of a small group composed of Christian ministers and a Jewish rabbi. The resulting conversations were among the most intense in my experience.

Carroll notes accurately that Augustine developed his thoughts in the context of a violent age that had grown increasingly dangerous for Jews. Christianity was the official religion of the Roman Empire. Christian leaders such as Ambrose and John Chrysostom used rhetoric that easily encouraged attacks on Jews. A consensus seemed to be emerging that the Jews could not be allowed to exist if they insisted on remaining Jews rather than converting to Christianity.

Augustine intervened. While he, like other Christian leaders of the period, insisted that Jews ought to repent and become Christians, he went further and developed a rationale for why “unrepentant” Jews should be protected from violence. Augustine argued that the survival of the Jews was part of the providence of God. The Jews were not to be slain. Instead, God permitted them to continue to survive as a living witness to the Old Testament prophecies concerning Christ. Their dispersion, along with their biblical texts, among the nations was part of God’s plan to prepare the way for the expansion of Christianity. The “homelessness and misery” of the Jews ought to be seen not only as God’s punishment, but as a positive witness to the truth of Christian claims.

Carroll correctly concludes that Augustine’s approach was remarkable for his time. He may overstate when he writes that “Christianity permitted Judaism to endure because of Augustine,” but not by much. In his own time and throughout the Middle Ages, Augustine’s dictum provided theological justification for church officials to attempt to protect Jewish populations from mob violence.

At the same time, though, Augustine’s scheme codified Christian ambivalence toward the Jews. While the church was to ensure the continued survival of the Jews for the sake of the “witness” they bore to Christianity, it was not to allow them to live comfortably. As Carroll puts it, church policy became “Let them survive, but not thrive!” Within such teaching lay the potential for explosions of violence whenever and wherever Jewish populations began to prosper economically or culturally. Carroll goes on to document several such cases, noting with sad irony that in most cases church leaders attempted to protect local Jewish populations but were unable to stand against Christian mobs.

Carroll argues throughout the book that such failure was and is inevitable so long as the church clings to the idea that Christianity has superseded Judaism. To his way of thinking, all efforts to have it both ways ”to believe that the Jews need to repent and become Christians yet allow for the preservation of an unrepentant population ”are doomed to failure. He argues that the church has failed God in its treatment of the Jews and pleads for a new approach.

In essence, Carroll urges that the church see itself as the way in which “God’s promise to Israel” is made available to gentiles, nothing more and nothing less. He insists that the church in no “way surpasses Israel or supersedes it.” He calls upon the church to acknowledge that it has betrayed Jesus through its attitude toward and treatment of the Jews, and he asks the church to repent and to change. To his way of thinking, both Jews and Christians are the people of God, and the sooner we acknowledge this to be true, the better.

Constantine’s Sword is a must-read. I first read it in the context of a small group composed of Christian ministers and a Jewish rabbi. The resulting conversations were among the most intense in my experience. For most of the Christians in the group, Carroll’s detailed treatment of Christian persecution of the Jews came as a devastating revelation. My Jewish friend was introduced to the history of Christian theology and came away with a better appreciation of how Christian actions have been conditioned by our theology. Speaking only for myself, I came away from the process convinced of Carroll’s thesis and prescription.

Carroll’s work is not without flaws. The scholarship upon which he draws is somewhat dated. His attempt to connect his personal journey with the story of the church and the Jews sometimes feels contrived. Still, these minor criticisms aside, Constantine’s Sword seems likely to become the most important and positive contribution to Jewish-Christian dialogue published in my lifetime.

Mike Smith is pastor of First Baptist Church in Murfreesboro, Tenn.