Leviticus 18:15-19

You shall not uncover the nakedness of your daughter-in-law. She is your son’s wife; you shall not uncover her nakedness.

You shall not uncover the nakedness of your brother’s wife; it is your brother’s nakedness.

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.

And you shall not marry a woman in addition to her sister as a second wife while she is alive, to uncover her nakedness.

‘Also you shall not approach a woman to uncover her nakedness during her menstrual impurity.