Deuteronomy 27:22

Blessings And Curses

²¹ ‘The one who has sexual intercourse with any animal is cursed.’
And all the people will say, ‘Amen!’
²² ‘The one who sleeps with his sister, whether his father’s daughter or his mother’s daughter is cursed.’
And all the people will say, ‘Amen!’
²³ ‘The one who sleeps with his mother-in-law is cursed.’
And all the people will say, ‘Amen!’

Sexual Relations

Leviticus 18:9

You are not to have sexual intercourse with your sister, either your father’s daughter or your mother’s, whether born at home or born elsewhere. You are not to have sex with her.

Leviticus 20:17

If a man marries his sister, whether his father’s daughter or his mother’s daughter, and they have sexual relations, it is a disgrace. They must be cut off publicly from their people. He has had sexual intercourse with his sister; he will bear his punishment.

Ezekiel 22:11

One man within you commits a detestable act with his neighbor’s wife; another wickedly defiles his daughter-in-law; and yet another violates his sister, his father’s daughter.

2 Samuel 13:1

Some time passed. David’s son Absalom had a beautiful sister named Tamar, and David’s son Amnon was infatuated with her.

2 Samuel 13:8-14

Then Tamar went to his house while Amnon was lying down. She took dough, kneaded it, made cakes in his presence, and baked them.