1 Chronicles 19:8-10

New International Version

⁸ On hearing this, David sent Joab out with the entire army of fighting men. ⁹ The Ammonites came out and drew up in battle formation at the entrance to their city, while the kings who had come were by themselves in the open country.

¹⁰ Joab saw that there were battle lines in front of him and behind him; so he selected some of the best troops in Israel and deployed them against the Arameans.