Incest: Defined and Forbidden

None of you are to approach any close relative to have sexual relations. I am the LORD. …

If a man lies with his father’s wife, he has uncovered his father’s nakedness. Both must surely be put to death; their blood is upon them.

If a man lies with his daughter-in-law, both must surely be put to death. They have acted perversely; their blood is upon them.

If a man marries his sister, whether the daughter of his father or of his mother, and they have sexual relations, it is a disgrace. They must be cut off in the sight of their people. He has uncovered the nakedness of his sister; he shall bear his iniquity.

You must not have sexual relations with the sister of your mother or your father, for it is exposing one’s own kin; both shall bear their iniquity. …

A man is not to marry his father’s wife, so that he will not dishonor his father’s marriage bed.

‘Cursed is he who sleeps with his father’s wife, for he has violated his father’s marriage bed.’ And let all the people say, ‘Amen!’ …

One man commits an abomination with his neighbor’s wife; another wickedly defiles his daughter-in-law; and yet another violates his sister, his own father’s daughter.

These were the sons of Reuben the firstborn of Israel. Though he was the firstborn, his birthright was given to the sons of Joseph son of Israel, because Reuben defiled his father’s bed. So he is not reckoned according to birthright.