"Love means never having to say you're sorry," proclaimed a sappy romance novel from the 1970s. I have come to believe the opposite, that love means precisely having to say you're sorry. A sense of guilt, vastly underappreciated, deserves our gratitude, for only such a powerful force can nudge us toward repentance and reconciliation with those we have harmed.

Yet guilt represents danger as well. In his novel The First Circle, Alexander Solzhenitsyn described a prisoner who obsessively marked a pink sheet of paper for every bad thought or "defect." I have known Christians who go through life with hyperattention to defects. Some raised in oppressive environments go through life afraid, heads down, fleeing anything that might be perceived as pleasure, and terrified that they are somehow offending one of God's laws.

Martin Luther, in his early days as a monk, would daily wear out his confessors with as many as six straight hours of introspection about minuscule sins and unhealthy thoughts. "My son, God is not angry with you: it is you who are angry with God," said one of his exasperated advisers. Luther eventually came to agree that his fear of sinning actually showed a lack of faith, both in his ability to live purely in an impure world, and in Christ's provision for his sin. "To diagnose smallpox you do not have to probe each pustule, nor do you heal each separately," he concluded.

H. L. Mencken's caricature of a Puritan—"a person with a haunting fear that someone, somewhere is happy"—hints at how far the church or society can stray from God's standards of right and wrong. Jesus himself was criticized by the "Puritans" of his day. A mature Christian learns to discriminate between false guilt inherited from parents, church, or ...