Sin was an extremely important and serious concern for the earliest Christians and the authors of the New Testament writings. Early Christians came to see the life and ministry of Jesus as challenging presumptions about the meanings of sin and faithfulness. This book provides a comprehensive treatment of different understandings of sin in early Christianity. Jeffrey S. Siker describes how the earliest Christian voices represented in the New Testament writings understood "sin" not only as a theological abstraction, but also as a real reflection upon human thought and behavior that violated right relationships with both other human beings and with God. Siker explores language about sin in relation to the Jewish and Greco-Roman contextual worlds of the New Testament writings, and examines the development and change of these worlds in relation to the modern concept of sin.