The military defeat of the Arameans by the Israelites triggered a dramatic shift in regional power dynamics and brought a sudden end to their alliance with the Ammonites. Once the servants of Hadadezer realized they had lost the war, they completely changed their approach. They chose to make peace with David, reaching an agreement that served as either a non-aggression pact or a formal surrender.
Under this new reality, the Arameans living close to the land of Israel were not entirely brought under David's control, and those living across the river were not conquered at all. Still, they agreed to accept his supreme authority over them. Following their failed military campaign, the Arameans decided they had experienced enough conflict. As a result, they refused to step in and provide any further military assistance to the Ammonites.