1 Chronicles 19:8

When the children of Ammon saw that they had made themselves odious to David, Hanun and the children of Ammon sent one thousand talents of silver to hire them chariots and horsemen out of Mesopotamia, and out of Arammaacah, and out of Zobah.

So they hired for themselves thirty-two thousand chariots, and the king of Maacah and his people, who came and encamped before Medeba. The children of Ammon gathered themselves together from their cities, and came to battle.

The children of Ammon came out, and put the battle in array at the gate of the city: and the kings who had come were by themselves in the field.

Now when Joab saw that the battle was set against him before and behind, he chose of all the choice men of Israel, and put them in array against the Syrians.