3 So there at Hebron, King David made a covenant before the Lord with all the elders of Israel. And they anointed him king of Israel. 4 David was thirty years old when he began to reign, and he reigned forty years in all.

Matthew Henry's Commentary on 2 Samuel 5:3-4

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.