Leviticus 16:17
16:17 Nobody is to be in the Meeting Tent when he enters to make atonement in the holy place until he goes out, and he has made atonement on his behalf, on behalf of his household, and on behalf of the whole assembly of Israel.
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.