2 Samuel 15:10-12
10-12Then Absalom sent undercover agents to all the tribes of Israel with the message, "When you hear the blast of the ram's horn trumpet, that's your signal: Shout, 'Absalom is king in Hebron!'" Two hundred men went with Absalom from Jerusalem. But they had been called together knowing nothing of the plot and made the trip innocently. While Absalom was offering sacrifices, he managed also to involve Ahithophel the Gilonite, David's advisor, calling him away from his hometown of Giloh. The conspiracy grew powerful and Absalom's supporters multiplied.
13Someone came to David with the report, "The whole country has taken up with Absalom!"