1 Chronicles 19:10-12

10And Joab saw that the front of the battle was against him before and behind; and he chose out of all the choice men of Israel, and put them in array against the Syrians;

11and the rest of the people he gave into the hand of Abishai his brother, and they set themselves in array against the children of Ammon.

12And he said, If the Syrians be too strong for me, then thou shalt help me; and if the children of Ammon be too strong for thee, then I will help thee.