The Bible’s outlawing of adultery is clear; one of the Ten Commandments forbids it, and Jesus invokes this commandment, expanding the sin to lustful thoughts. Despite these teachings against adultery, however, the Bible does leave room for forgiveness, in both the Old and New Testaments.

The Definition of Adultery

Adultery is not the same as fornication. Specifically, adultery is sex between someone who is married and someone other than his or her spouse. The Hebrew term "na'aph" can refer either to the act by a man or a woman, and the word is also used for worshippers of false idols. Both are a form of betrayal. Adultery is, therefore, not merely sexual sin. Theologian and pastor Neil S. Wilson points out that the spiritual implications of adultery-as-betrayal reflects on the spiritual “marriage” of the church with Christ as well as on the initial covenant of the Jews with God.

David Begs for Forgiveness

Despite the seriousness of adultery, God can forgive a remorseful adulterer. David committed adultery with Bathsheba, compounding his crime by having her husband killed. His sin is so egregious that David and Bathsheba’s first son dies as a punishment, but God forgives the woeful king, allowing him a long life and more sons, including Solomon. Psalm 51 is David’s eloquent plea for forgiveness, offering to God his “broken spirit” and “broken and contrite heart.”

Hosea Forgives His Wife

The Old Testament prophet Hosea at first denounces his wife, vowing to reject the children she adulterously conceived and to deny her food and clothing. God had instructed Hosea to marry a woman whose unfaithfulness would mirror the Israelites’ unfaithfulness to God. Later, God tells Hosea to forgive his wife and claim her children, just as he will forgive the Israelites. Psychologist and theologian J. Harold Ellens, in his book “Sex in the Bible,” explains that Hosea’s mercy toward his wife serves as a metaphor for God’s relationship with humanity, made explicit when God tells him, “I will say to those called ‘Not my people,’ ‘You are my people.’”

Jesus Protects the Adulteress

In the New Testament, Jesus repeatedly forgives sinners, even his own torturers. The Gospel of John has Jesus interceding for an adulterous woman. The Pharisees bring the unnamed woman to court to test Jesus on Jewish law, but he refuses to debate. Instead, he tells the crowd that anyone who is “without sin” should throw the first stone. Instead of killing her, the crowd disperses, and Jesus tells the woman, “Then neither do I condemn you.... Go now and leave your life of sin.”