2 Samuel 10:6-11

And when the children of Ammon saw that they were become odious to David, the children of Ammon sent and hired the Syrians of Beth-rehob, and the Syrians of Zobah, twenty thousand footmen, and the king of Maacah with a thousand men, and the men of Tob twelve thousand men. And when David heard of it, he sent Joab, and all the host of the mighty men. And the children of Ammon came out, and put the battle in array at the entrance of the gate: and the Syrians of Zobah and of Rehob, and the men of Tob and Maacah, were by themselves in the field. Now when Joab saw that the battle was set against him before and behind, he chose of all the choice men of Israel, and put them in array against the Syrians: and the rest of the people he committed into the hand of Abishai his brother; and he put them in array against the children of Ammon. And he said, If the Syrians be too strong for me, then thou shalt help me; but if the children of Ammon be too strong for thee, then I will come and help thee.