2 Samuel 16:19-22
English Standard Version
20Then Absalom said to Ahithophel, "Give your counsel. What shall we do?"
21Ahithophel said to Absalom, "Go in to your father 's concubines, whom he has left to keep the house, and all Israel will hear that you have made yourself a stench to your father, and the hands of all who are with you will be strengthened."
22So they pitched a tent for Absalom on the roof. And Absalom went in to his father 's concubines in the sight of all Israel.