51 Then all the tribes of Israel came to David at Hebron and spoke, saying, "Indeed we are your bone and your flesh. 2 Also, in time past, when Saul was king over us, you were the one who led Israel out and brought them in; and the Lord said to you, 'You shall shepherd My people Israel, and be ruler over Israel.' " 3 Therefore all the elders of Israel came to the king at Hebron, and King David made a covenant with them at Hebron before the Lord. And they anointed David king over Israel.
Matthew Henry's Commentary on 2 Samuel 5:1-3
Commentary on 2 Samuel 5:1-5
(Read 2 Samuel 5:1-5)
David was anointed king a third time. His advances were gradual, that his faith might be tried, and that he might gain experience. Thus his kingdom typified that of the Messiah, which was to come to its height by degrees. Thus Jesus became our Brother, took upon him our nature, dwelt in it that he might become our Prince and Saviour: thus the humbled sinner takes encouragement from the endearing relation, applies for his salvation, submits to his authority, and craves his protection.