1 Chronicles 19:18-19

Modern English Version

¹⁸ But the Arameans fled before Israel, and David killed seven thousand chariot drivers and forty thousand infantry men of the Arameans, and killed Shophak, the commander of the army.

¹⁹ And when the servants of Hadadezer saw that they were defeated before Israel, they negotiated peace with David and served him.

So the Arameans were not willing to aid the Ammonites in battle again.