Leviticus 18:6, 9, 14

“You are not to come near  any close relative  for sexual intercourse;  I am the LORD.

You are not to have sexual intercourse with your sister, either your father’s daughter or your mother’s,  whether born at home or born elsewhere. You are not to have sex with her.

You are not to violate the intimacy that belongs to  your father’s brother by approaching his wife to have sexual intercourse; she is your aunt.