2 Samuel 10:6-11

The Ammonites knew that they had insulted David. So they hired twenty thousand Aramean foot soldiers from Beth Rehob and Zobah. They also hired the king of Maacah with a thousand men and twelve thousand men from Tob. When David heard about this, he sent Joab with the whole army. The Ammonites came out and prepared for battle at the city gate. The Arameans from Zobah and Rehob and the men from Tob and Maacah were out in the field by themselves. Joab saw that there were enemies both in front of him and behind him. So he chose some of the best soldiers of Israel and sent them out to fight the Arameans. Joab put the rest of the army under the command of Abishai, his brother. Then he sent them out to fight the Ammonites. Joab said to Abishai, “If the Arameans are too strong for me, you must help me. Or, if the Ammonites are too strong for you, I will help you.