Leviticus 18:6-8

King James Version

⁶ None of you shall approach to any that is near of kin to him, to uncover their nakedness: I am the Lord.

⁷ The nakedness of thy father, or the nakedness of thy mother, shalt thou not uncover: she is thy mother; thou shalt not uncover her nakedness.

⁸ The nakedness of thy father's wife shalt thou not uncover: it is thy father's nakedness.