Deuteronomy 22:30 in the King James Version
A man shall not take his father’s wife, nor discover his father’s skirt.
Context
29 then the man who lay with her shall give to the lady’s father fifty shekels of silver. She shall be his wife, because he has humbled her. He may not put her away all his days.
30 A man shall not take his father’s wife, and shall not uncover his father’s skirt.