Leviticus 18:7
You must not expose the nakedness of your father by having sexual relations with your mother. She is your mother; you must not have sexual relations with her.
Berean Standard Bible
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.
“‘You shall not uncover the nakedness of your father, nor the nakedness of your mother: she is your mother. You shall not uncover her nakedness.