Leviticus 18:11

“ ‘If a man takes his sister—his father’s daughter, or his mother’s daughter—and sees her nakedness, and she sees his nakedness, it is a shameful thing. They shall be cut off in the sight of the children of their people. He has uncovered his sister’s nakedness. He shall bear his iniquity.

The man, the master of the house, went out to them, and said to them, “No, my brothers, please don’t act so wickedly; since this man has come into my house, don’t do this folly.

I took my concubine and cut her in pieces, and sent her throughout all the country of the inheritance of Israel; for they have committed lewdness and folly in Israel.

The sons of Jacob came in from the field when they heard it. The men were grieved, and they were very angry, because he had done folly in Israel in lying with Jacob’s daughter, a thing ought not to be done.

‘Cursed is he who lies with his sister, his father’s daughter or his mother’s daughter.’ All the people shall say, ‘Amen.’

She answered him, “No, my brother, do not force me! For no such thing ought to be done in Israel. Don’t you do this folly.

One has committed abomination with his neighbor’s wife; and another has lewdly defiled his daughter-in-law. Another in you has humbled his sister, his father’s daughter.

Then Abimelech called Abraham, and said to him, “What have you done to us? How have I sinned against you, that you have brought on me and on my kingdom a great sin? You have done deeds to me that ought not to be done!”

Shechem the son of Hamor the Hivite, the prince of the land, saw her. He took her, lay with her, and humbled her.

“ ‘You shall not uncover the nakedness of your sister, the daughter of your father, or the daughter of your mother, whether born at home or born abroad.

then the man who lay with her shall give to the lady’s father fifty shekels of silver. She shall be his wife, because he has humbled her. He may not put her away all his days.

He said to him, “Why, son of the king, are you so sad from day to day? Won’t you tell me?” Amnon said to him, “I love Tamar, my brother Absalom’s sister.”

I saw among the simple ones. I discerned among the youths a young man void of understanding,

I turned around, and my heart sought to know and to search out, and to seek wisdom and the scheme of things, and to know that wickedness is stupidity, and that foolishness is madness.

Out of the same mouth comes blessing and cursing. My brothers, these things ought not to be so.