2 Samuel 15:10-13
But Absalom sent spies throughout all the tribes of Israel, saying, As soon as ye hear the sound of the trumpet, then ye shall say, Absalom reigneth in Hebron. And with Absalom went two hundred men out of Jerusalem, that were called; and they went in their simplicity, and they knew not any thing. And Absalom sent for Ahithophel the Gilonite, David's counseller, from his city, even from Giloh, while he offered sacrifices. And the conspiracy was strong; for the people increased continually with Absalom. And there came a messenger to David, saying, The hearts of the men of Israel are after Absalom.