When the Ammonites realized they had made themselves repulsive to David, Hanun and the Ammonites sent 38 tons of silver to hire chariots and horsemen from Aram-naharaim, Aram-maacah, and Zobah.

and they hire to them two and thirty thousand chariots, and the king of Maachah and his people, and they come in and encamp before Medeba, and the sons of Ammon have been gathered out of their cities, and come in to the battle.