This study examines how St. Augustine uses the motif Christus Sacerdos to synthesize the entire mystery of Christ, to define Christian identity, and to oppose counter-identities and doctrines, especially those symbolized by pagan priesthoods. The bishop of Hippo continually joins these three elements Christology, Christian identity, and polemic so that the doctrine of Christ is always related to its implications for life -on the ground-. Augustine shows how the doctrine of Christ entails an identity and an ideal for Christians, defining who they are and what they are to become. He...