2 Samuel 16:20-23

Absalom said to Ahithophel, “Tell us what we should do.” Ahithophel said, “Your father left behind some of his slave women to take care of the palace. Have sexual relations with them. Then all Israel will hear that your father is your enemy, and all your people will be encouraged to give you more support.” So they put up a tent for Absalom on the roof of the palace where everyone in Israel could see it. And Absalom had sexual relations with his father’s slave women. At that time people thought Ahithophel’s advice was as reliable as God’s own word. Both David and Absalom thought it was that reliable.