The nakedness of thy father's wife shalt thou not uncover: it is thy father's nakedness.
If a man sleeps with his father's wife, he has shamed his father. Both of them must be put to death; their blood is on their own hands.
While Israel was living in that region, Reuben went in and slept with his father's concubine Bilhah, and Israel heard about it. Jacob had 12 sons:
Turbulent as water, you will no longer excel, because you got into your father's bed and you defiled it-- he got into my bed.
"A man is not to marry his father's wife; he must not violate his father's marriage bed.
'Cursed is the one who sleeps with his father's wife, for he has violated his father's marriage bed.' And all the people will say, 'Amen!'
2 Samuel 16:21
Ahithophel replied to Absalom, "Sleep with your father's concubines he left to take care of the palace. When all Israel hears that you have become repulsive to your father, everyone with you will be encouraged."
2 Samuel 16:22
So they pitched a tent for Absalom on the roof, and he slept with his father's concubines in the sight of all Israel.
Men within you have sexual intercourse with [their] father's wife, and violate women during their menstrual impurity.
They trample the heads of the poor on the dust of the ground and block the path of the needy. A man and his father have sexual relations with the same girl, profaning My holy name.
1 Corinthians 5:1
It is widely reported that there is sexual immorality among you, and the kind of sexual immorality that is not even condoned among the Gentiles-- a man is living with his father's wife.