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.
Leviticus 20:11
And the man that lieth with his father's wife hath uncovered his father's nakedness. Both of them shall surely be put to death: their blood shall be upon them.
Ezekiel 22:10
In thee have they uncovered their fathers' nakedness. In thee have they humbled her that was set apart for pollution.