Read 2 Samuel 8:13-15 KJV
2 Samuel 8
13 And David gat him a name when he returned from smiting of the Syrians in the valley of salt, being eighteen thousand men.
14 And he put garrisons in Edom; throughout all Edom put he garrisons, and all they of Edom became David's servants. And the LORD preserved David whithersoever he went.
15 And David reigned over all Israel; and David executed judgment and justice unto all his people.