Adultery, according to ancient Jewish, Greek, and Roman law, is sexual intercourse between a married woman and a man other than her husband. The Bible forbids adultery in the Ten Commandments (Exodus 20:14).
- And the man that committeth adultery with another man's wife, even he that committeth adultery with his neighbor's wife, the adulterer and the adulteress shall surely be put to death. (Leviticus 20:10)
Jesus said that a man commits adultery in his heart by lustfully looking at a woman. (Matthew 5:28) Sexual intercourse by a married man or woman outside marriage is considered adultery under modern law, although it is hardly ever punished anymore. It is also a sin regardless of whether the adulterous spouse had the "agreement" of the other, such as in an open marriage (though in secular culture adultery has come to imply lack of consent/approval)
Adultery may ruin trust between husband and wife and break up families. It is contrary to the traditional marriage pronouncement derived from Matthew 19:6: "Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder." It also breaks the promise that the bride and groom make to each other in virtually every form of marriage ceremony observed in the U.S.—even secular observances conducted in judge's chambers, or in vows written by the couple themselves.
Other effects of adultery, if committed by someone who claims to be a Christian, include invalidating one's Christian witness, destroying one's business because of a perception that one cannot be trusted, and leading others to conclude that all Christians are hypocrites. Also, since adultery is a form of sexual immorality, the general harms to society from sexual immorality arise from adultery as well.
Pro-feminist author Thomas Boslooper regarded Jesus as elevating the status of women when, as commonly supposed, he confronted the townspeople over their plan to kill the woman caught in adultery. Scholars are divided regarding whether the story is a fabrication due to New Testament manuscript variations.
Marital infidelity and evolutionary belief
Notes and references
- Eg, Leviticus 20:10 and Deuteronomy 22:22 describe adultery as between a man and another man's wife. See also , .
- The ACLU has been unable to find an adulterer who is willing to challenge a prosecution. 
- 40 Consequences of Adultery, from FamilyLife Ministries