2 Samuel 15:7-10

7And it came to pass at the end of forty years, that Absalom said to the king, I pray thee, let me go and pay in Hebron my vow which I have vowed to Jehovah.

8For thy servant vowed a vow while I abode in Geshur in Syria, saying, If Jehovah shall bring me again indeed to Jerusalem, then I will serve Jehovah.

9And the king said to him, Go in peace. And he rose up and went to Hebron.

10And Absalom sent emissaries into all the tribes of Israel, saying, When ye hear the sound of the trumpet, ye shall say, Absalom reigns in Hebron.