2Sam 15:7-10

7At the end of four years Absalom said to the king, “Please let me go to Hebron and pay the vow that I have made to the Lord.8For your servant made a vow while I lived at Geshur in Aram: If the Lord will indeed bring me back to Jerusalem, then I will worship the Lord in Hebron.”9The king said to him, “Go in peace.” So he got up, and went to Hebron.10But Absalom sent secret messengers throughout all the tribes of Israel, saying, “As soon as you hear the sound of the trumpet, then shout: Absalom has become king at Hebron!”