2 Samuel 15:10-13

10But Absalom sent spies throughout all the tribes of Israel, saying, “As soon as you hear the sound of the trumpet, you shall say, ‘Absalom is king in Hebron.’ ”

11Then two hundred men from Jerusalem who were invited [as guests to his sacrificial feast] went with Absalom. They went innocently and knew nothing [about his plan against David].

12And Absalom sent for Ahithophel the Gilonite, David’s counselor, from his city Giloh, while he was offering sacrifices. And the conspiracy grew strong, for the people with Absalom increased continually.

13Then a messenger came to David, saying, “The hearts of the men of Israel are with Absalom.”