Leviticus 18:9

18:9 You must not have sexual intercourse with your sister, whether she is your father’s daughter or your mother’s daughter, whether she is born in the same household or born outside it; you must not have sexual intercourse with either of them.

Leviticus 18:11

18:11 You must not have sexual intercourse with the daughter of your father’s wife born of your father; she is your sister. You must not have intercourse with her.