The Arameans fled before Israel. David killed 700 Aramean charioteers and 40,000 foot soldiers. He also struck down Shobach, the general in command of the army, who died there.
When David was informed, he gathered all Israel, crossed the Jordan River, and marched against them. David deployed his army against the Arameans for battle and they fought against him.
When Hadadezer’s subjects saw they were defeated by Israel, they made peace with David and became his subjects. The Arameans were no longer willing to help the Ammonites.