Leviticus 20:17-19

New Revised Standard Version, Anglicised Catholic Edition

¹⁷ 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 their people; he has uncovered his sister’s nakedness, he shall be subject to punishment. ¹⁸ If a man lies with a woman having her sickness and uncovers her nakedness, he has laid bare her flow and she has laid bare her flow of blood; both of them shall be cut off from their people. ¹⁹ You shall not uncover the nakedness of your mother’s sister or of your father’s sister, for that is to lay bare one’s own flesh; they shall be subject to punishment.