2 Samuel 16:21-23

21And Ahithophel said to Absalom, Go in to thy father's concubines, whom he has left to keep the house; and all Israel shall hear that thou art become odious with thy father; and the hands of all that are with thee shall be strong. 22So they spread a tent for Absalom upon the roof; and Absalom went in to his father's concubines in the sight of all Israel. 23And the counsel of Ahithophel, which he counselled in those days, was as if a man had inquired of the word of 1God: so was all the counsel of Ahithophel both with David and with Absalom.