1 Chronicles 18:13

And he put garrisons in Edom; and all the Edomites became David's servants. Thus the LORD preserved David whithersoever he went.

He put garrisons in Edom; and all the Edomites became David's servants. This annexation of Edom enlarged the border of Israel on the southeast to the Red Sea, conformably to the divine promise (Exodus 23:31), and gave him command of its ports.