2 Samuel 15:7-10

7After four years, Absalom said to the king, “Let me go to Hebron to offer a sacrifice to the Lord and fulfill a vow I made to him.

8For while your servant was at Geshur in Aram, I promised to sacrifice to the Lord in Hebron if he would bring me back to Jerusalem.”

9“All right,” the king told him. “Go and fulfill your vow.” So Absalom went to Hebron.

10But while he was there, he sent secret messengers to all the tribes of Israel to stir up a rebellion against the king. “As soon as you hear the ram’s horn,” his message read, “you are to say, ‘Absalom has been crowned king in Hebron.’”