2 Samuel 10:10 (BSB)

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

From 2 Samuel 10. Also in the ESV.

Commentary on 2 Samuel 10:10

• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on 2 Samuel 10:6-14: Here we have, I. The preparation which the Ammonites made for war, Sa2 10:6. They saw they had made themselves very odious to David and obnoxious to his just displeasure. This they might easily have foreseen when they abused his ambassadors, which was no other than a challenge to war, and a bold defiance of him.
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on 2 Samuel 10:10: And the rest of the people he delivered into the hands of Abishai his brother,.... Who was a commander under him, and a very valiant man; and thus, as his enemy had two armies, he divided his into two parts, that he might the better attack them: that he might put them in array against the children of Ammon: draw them up in a line...
• Keil & Delitzsch (Lutheran), Biblical Commentary on the Old Testament on 2 Samuel 10:9-11: 2Sa 10:9-11 When Joab saw that “the front of the war was (directed) against him both before and behind,” he selected a picked body out of the Israelitish army, and posted them (the picked men) against the children of Aram (i.e., the Syrians). The rest of the men he gave to his brother Abishai, and stationed them against the Ammonites.