1 Chronicles 19:7-15

7So they hired for themselves thirty-two thousand chariots, as well as the king of Maacah with his troops, who came and camped near Medeba while the Ammonites were mustered from their cities and marched out for battle.

8On hearing this, David sent Joab and the entire army of mighty men. 9The Ammonites marched out and arrayed themselves for battle at the entrance to the city, while the kings who had come stayed by themselves in the open country.

10When Joab saw the battle lines before him and behind him, he selected some of the best men of Israel and arrayed them against the Arameans. 11And he placed the rest of the troops under the command of his brother Abishai, who arrayed them against the Ammonites.

12“If the Arameans are too strong for me,” said Joab, “then you will come to my rescue. And if the Ammonites are too strong for you, then I will come to your rescue. 13Be strong and let us fight bravely for our people and for the cities of our God. May the LORD do what is good in His sight.”

14So Joab and his troops advanced to fight the Arameans, who fled before him. 15When the Ammonites saw that the Arameans had fled, they too fled before Joab’s brother Abishai, and they entered the city. So Joab went back to Jerusalem.