Leviticus 20:17

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 the children of their people . He has uncovered his sister’s nakedness , and he shall bear his iniquity .

“‘If a man marries his sister, the daughter of either his father or his mother, and they have sexual relations, it is a disgrace. They are to be publicly removed from their people. He has dishonored his sister and will be held responsible.

And if a man shall take his sister, his father's daughter, or his mother's daughter, and see her nakedness, and she see his nakedness; it is a wicked thing; and they shall be cut off in the sight of their people : he hath uncovered his sister's nakedness; he shall bear his iniquity.