2 Samuel 15:7 KJV
And it came to pass after forty years, that Absalom said unto the king, I pray thee, let me go and pay my vow, which I have vowed unto the Lord, in Hebron.
2 Samuel 15:7, King James Version
In context
6 And on this manner did Absalom to all Israel that came to the king for judgment: so Absalom stole the hearts of the men of Israel.
7 And it came to pass after forty years, that Absalom said unto the king, I pray thee, let me go and pay my vow, which I have vowed unto the Lord, in Hebron.
8 For thy servant vowed a vow while I abode at Geshur in Syria, saying, If the Lord shall bring me again indeed to Jerusalem, then I will serve the Lord.