Leviticus 18:6, 9, 14

“You must never have sexual relations with a close relative, for I am the LORD.

“Do not have sexual relations with your sister or half sister, whether she is your father’s daughter or your mother’s daughter, whether she was born into your household or someone else’s.

“Do not violate your uncle, your father’s brother, by having sexual relations with his wife, for she is your aunt.