Leviticus 18:17-19

American Standard Version

¹⁷ Thou shalt not uncover the nakedness of a woman and her daughter; thou shalt not take her son’s daughter, or her daughter’s daughter, to uncover her nakedness; they are near kinswomen: it is ^[a]wickedness. ¹⁸ And thou shalt not take a wife to her sister, to be a rival to her, to uncover her nakedness, besides the other in her life-time.

¹⁹ And thou shalt not approach unto a woman to uncover her nakedness, as long as she is ^[b]impure by her uncleanness.