Punishment: Death Penalty for Adultery
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Leviticus 20:10
If a man commits adultery with another man’s wife—with the wife of his neighbor—both the adulterer and the adulteress must surely be put to death.
Deuteronomy 22:24
you must take both of them out to the gate of that city and stone them to death—the young woman because she did not cry out in the city, and the man because he has violated his neighbor’s wife. So you must purge the evil from among you.