So David reigned over all Israel. And David administered justice and equity to all his people.
David was not so engaged in his wars abroad as to neglect the administration of the government at home. I. His care extended itself to all the parts of his dominion: He reigned over all Israel (Sa2 8:15); not only he had a right to reign over all the tribes, but he did so; they were all safe under his protection, and shared in the fruits of his good government.
Commenting on 2 Samuel 8:15-18
And David reigned over all Israel,.... Not only over Judah, but over all the tribes of Israel, and over the whole land of Canaan, as promised to Abraham, Gen 15:18; reaching to the river Euphrates, as Syria did, now conquered by David: and David executed judgment and justice unto all his people; when he returned from his wars, he heard and tried all causes impartially...
HIS REIGN. (Sa2 8:15-18) David executed judgment and justice unto all his people--Though involved in foreign wars, he maintained an excellent system of government at home, the most eminent men of the age composing his cabinet of ministers.