2 Samuel 10:7-14

7On hearing this, David sent Joab and the entire army of mighty men. 8The Ammonites marched out and arrayed themselves for battle at the entrance of the city gate, while the Arameans of Zobah and Rehob and the men of Tob and Maacah were by themselves in the open country.

9When 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. 10And he placed the rest of the troops under the command of his brother Abishai, who arrayed them against the Ammonites.

11“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. 12Be 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.”

13So Joab and his troops advanced to fight the Arameans, who fled before him. 14When the Ammonites saw that the Arameans had fled, they too fled before Abishai, and they entered the city. So Joab returned from fighting against the Ammonites and came to Jerusalem.