In this book, Paul Moser explains how self-sacrificial righteousness of a reparative kind is at the heart of Paul's gospel of God. He also shows how divine self-sacrifice authenticates that gospel via human reciprocity toward God in reconciliation. A basis for this reciprocity lies in a teaching of ancient Judaism that humans are to reciprocate toward God for the sake of an interpersonal relationship that is righteous and reconciled through voluntary self-sacrifice to God. Moser demonstrates that Paul's gospel calls for faith, including trust, in God as reciprocity in human self-sacrifice toward God. Although widely neglected by interpreters, this theme brings moral and evidential depth to Paul's good news of reparative redemption from God. Moser's study thus enables a new understanding of some of the controversial matters regarding Paul's message in a way that highlights the coherence and profundity of his message.