Leviticus 18:17-19

New Catholic Bible

¹⁷ You shall not uncover the nakedness of both a woman and her daughter. Nor shall you uncover the nakedness of her son’s daughter nor her daughter’s daughter. They are her close relations. It would be shameful. ¹⁸ You shall not take the sister of your wife while she is still alive, uncovering her nakedness. They would be rivals.

¹⁹ “ ‘You shall not approach a woman to uncover her nakedness during her menstrual impurity.