2 Samuel 16:20-22

Absalom said to Ahithophel, “Give us your advice. What should we do?” Ahithophel answered, “Sleep with your father’s concubines whom he left to take care of the palace. Then all Israel will hear that you have made yourself obnoxious to your father, and the hands of everyone with you will be more resolute.” So they pitched a tent for Absalom on the roof, and he slept with his father’s concubines in the sight of all Israel.