Thou shalt not uncover the nakedness of a woman and her daughter, neither shalt thou take her son’s daughter, or her daughter’s daughter, to uncover her nakedness; for they are her near kinswomen: it is wickedness.

You must not have sexual relations with both a woman and her daughter. You are not to marry her son’s daughter or her daughter’s daughter and have sexual relations with her. They are close relatives; it is depraved.