2 Samuel 15:31; 2 Samuel 15:34

31 And it was told David, "Ahithophel is among the conspirators with Absalom." And David said, "O LORD, please turn the counsel of Ahithophel into foolishness."

34 But if you return to the city and say to Absalom, 'I will be your servant, O king; as I have been your father's servant in time past, so now I will be your servant,' then you will defeat for me the counsel of Ahithophel.