Leviticus 20:10 If there is a man who commits adultery with another man's wife, one who commits adultery with his friend's wife, the adulterer and the adulteress shall surely be put to death.

Proverbs 6:29 So is the one who goes in to his neighbor's wife; Whoever touches her will not go unpunished.

Matthew 5:27 "You have heard that it was said, 'YOU SHALL NOT COMMIT ADULTERY';

Matthew 5:28 but I say to you that everyone who looks at a woman with lust for her has already committed adultery with her in his heart.

1 Corinthians 6:9 Or do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor homosexuals,

Hebrews 13:4 Marriage is to be held in honor among all, and the marriage bed is to be undefiled; for fornicators and adulterers God will judge. (NASB ©1995)