2 Samuel 5:1-4

1Then all the tribes of Israel came to David at Hebron and said, “Behold, we are your bone and your flesh.

2In times past, when Saul was king over us, it was you who led Israel out [to war] and brought Israel in [from battle]. And the Lord told you, ‘You shall shepherd My people Israel and be ruler over them.’ ”

3So all the elders (tribal leaders) of Israel came to the king at Hebron, and King David made a covenant with them at Hebron before the Lord; and they anointed him king over Israel.

4David was thirty years old when he became king, and he reigned forty years.