Deuteronomy 22:21-22

21she shall be brought to the door of her father’s house, and there the men of her city will stone her to death. For she has committed an outrage in Israel by being promiscuous in her father’s house. So you must purge the evil from among you.1

22If a man is found lying with another man’s wife, both the man who slept with her and the woman must die. You must purge the evil from Israel.