2 Samuel 16:20-23

Then Absalom turned to Ahithophel and asked him, “What should I do next?” Ahithophel told him, “Go and sleep with your father’s concubines, for he has left them here to look after the palace. Then all Israel will know that you have insulted your father beyond hope of reconciliation, and they will throw their support to you.” So they set up a tent on the palace roof where everyone could see it, and Absalom went in and had sex with his father’s concubines. Absalom followed Ahithophel’s advice, just as David had done. For every word Ahithophel spoke seemed as wise as though it had come directly from the mouth of God.