Leviticus 18:17-18

New American Standard Bible

^17 (A)You shall not uncover the nakedness of a woman and of her daughter, nor shall you take her son’s daughter or her daughter’s daughter, to uncover her nakedness; they are blood relatives. It is an outrageous sin. ¹⁸ And you shall not ^[a]marry a woman in addition to her sister ^[b]as a second wife while she is alive, to uncover her nakedness.