Leviticus 18:15

15 Never have sexual intercourse with your daughter-in-law. She is your son's wife. Never have sexual intercourse with her.

Leviticus 18:15 Meaning and Commentary

Leviticus 18:15

Thou shall not uncover the nakedness of thy daughter in law,
&c.] Shall not he with her in his son's lifetime, or marry her after his death: she [is] that son's wife;
and so one flesh with him, and who is of the same flesh and blood with his father, and therefore the nearness of the relation forbids such incestuous copulation or marriage: thou shall not uncover her nakedness;
or have carnal knowledge of her, whether in the life or after the death of his son, even then marriage with her is not lawful.

Leviticus 18:15 In-Context

13 Never have sexual intercourse with your mother's sister. She is your maternal aunt.

14 Never have sexual intercourse with the wife of your father's brother. She, too, is your aunt.

15 Never have sexual intercourse with your daughter-in-law. She is your son's wife. Never have sexual intercourse with her.

16 Never have sexual intercourse with your sister-in-law. She is your brother's wife.

17 Never have sexual intercourse with a woman and her daughter or a woman and her granddaughter. They are related. Doing this is perverted.