2 Samuel 8:3

David smote also Hadadezer, the son of Rehob, king of Zobah, as he went to recover his border at the river Euphrates.

Ver. 3. David smote also Hadadezer.] An ambitious and turbulent prince, who began to grow exceeding potent; and had already, as it may seem, subdued Damascus, and was now formidable to the Israelites. Saul had had wars with his father Zobah, 1Sa 14:47 and haply he might pretend that old quarrel, or the conquest of Canaan by his predecessor Cushanrishathaim.

As he went to recover.] And so must needs pass through part of Judea on the other side Jordan, or not far from it. And so if he had returned a conqueror, was like enough to invade it; for ambition is restless, and never saith, It is enough.