Sin, Keller notes, is a frequently misunderstood concept associated with the Christian faith. Many people, both believers and nonbelievers, hold a simplistic view in which sin is considered as a crime against God, for which God will punish the offender. This oversimplification leads some to reject Christianity for what they perceive as a judgmental and legalistic tone.

By contrast, Keller holds that sin is an integral part of the “good news” of the Christian message. Keller describes encouraging a man who had come to him for counseling: “[T]he good news was—he was a sinner. Because he was a sinner he wasn’t simply the helpless victim of psychological drives or social systems” (166). Acknowledging the reality of sin opens up the possibility of repentance and healing in a way that is not possible within a victimization mindset.

Keller defines sin not simply as the breaking of divine commandments but, in a more fundamental sense, as the replacement of God in one’s life with other things: “[T]he primary way to define sin is not just the doing of bad things, but the making of good things into ultimate things.