Leviticus 18:6
"None of you shall approach any one of his close relatives to uncover nakedness. I am the LORD.
Leviticus 18:7-19
You shall not uncover the nakedness of your father, which is the nakedness of your mother; she is your mother, you shall not uncover her nakedness.
Leviticus 20:11-12
If a man lies with his father's wife, he has uncovered his father's nakedness; both of them shall surely be put to death; their blood is upon them.
Leviticus 20:17-21
"If a man takes his sister, a daughter of his father or a daughter of his mother, and sees her nakedness, and she sees his nakedness, it is a disgrace, and they shall be cut off in the sight of the children of their people. He has uncovered his sister's nakedness, and he shall bear his iniquity.