2 Samuel 15:30-31

30But David continued to go up the Mount of Olives. He was weeping as he went. He had covered his head and he was not wearing any shoes on his feet. All the people with him also covered their heads and they wept as they went up the hill.

31Someone told David that his advisor, Ahithophel, had now joined with Absalom and his men. So David prayed, ‘Lord, please cause Ahithophel to give them foolish advice.’