2 Samuel 16:21-22

16:21 Ahithophel replied to Absalom, “Have sex with your father’s concubines whom he left to care for the palace. All Israel will hear that you have made yourself repulsive to your father. Then your followers will be motivated to support you.” 16:22 So they pitched a tent for Absalom on the roof, and Absalom had sex with his father’s concubines in the sight of all Israel.