1 Chronicles 19:7-9

7So they hired for themselves 32,000 chariots and the king of Maacah and his troops, who came and camped before Medeba. And the Ammonites gathered together from their cities and came to battle.

8When David heard about it, he sent Joab and all the army of courageous men.

9The Ammonites came out and lined up in battle formation at the entrance of the city [Medeba], while the kings who had come were by themselves in the open country.