1 Chronicles 19:10 -

The meaning in brief of this Terse is that, as Joab found there were practically two enemies, and two armies to face, he avoided the mistake of being shut up between them more than necessary, and divided his own hosts. He took the flower of all, under his own command, to face the Syrians in the field, who were the most formidable of the enemy. The rest he put under his brother Abishai, to face the Ammonites at the gate, i.e. of the city Medeba. The plan succeeded, for if Abishai had only done as much as hold back the Ammonites awhile, so soon as they saw the Syrians break and flee they knew that Joab and his army would be free to "help" Abishai.