1 Chronicles 19:7-9

7So they hired for themselves 32,000 chariots, and the king of Maacah and his people, who came and camped before 1Medeba. And the sons of Ammon gathered together from their cities and came to battle. 8When David heard of it, he sent Joab and all the army, the mighty men. 9The sons of Ammon came out and drew up in battle array at the entrance of the city, and the kings who had come were by themselves in the field.