Deuteronomy 27:22

‘The nakedness of your sister, either your father’s daughter or your mother’s daughter, whether born at home or born outside, their nakedness you shall not uncover.

‘If there is a man who takes his sister, his father’s daughter, or his mother’s daughter, so that he sees her nakedness and she sees his nakedness, it is a disgrace; and they shall be cut off in the sight of the sons of their people. He has uncovered his sister’s nakedness; he bears his guilt.

But he was not willing to listen to her voice. Now he was stronger than she, so he violated her and lay with her.

“Indeed all Israel has trespassed against Your law, even turning aside, not listening to Your voice; so the curse has been poured out on us, along with the oath which is written in the law of Moses the servant of God, for we have sinned against Him.

Otherwise if you bless in the spirit only, how will the one who fills the place of the uninformed say the “Amen” at your giving of thanks, since he does not know what you are saying?