Leviticus 18:17-20

17The nakedness of a woman and her daughter shalt thou not uncover; thou shalt not take her son's daughter, nor her daughter's daughter, to uncover her nakedness: they are her near relations: it is wickedness.

18And thou shalt not take a wife to her sister, to vex her, to uncover her nakedness beside her, during her life.

19And thou shalt not approach a woman in the separation of her uncleanness to uncover her nakedness.

20And thou shalt not lie carnally with thy neighbour's wife, to become unclean with her.