When Joab saw that he had two fronts to fight, before and behind, he took his pick of the best of Israel and deployed them to confront the (stronger enemy). The rest of the army he put under the command of Abishai, his brother, and deployed them to confront the (weaker enemy). 2 Samuel 10:9,10
Maximize the potential that God has provided. Doug Sager, Christian Preacher

Joab to Abishai, "If the Syrians are too strong for me, then you shall help me; but if the people of Ammon are too strong for you, then I will come and help you. 2 Samuel 10:11

We serve under the same banner, and, instead of shutting up our sympathies within the narrow limits of our own regiment, and even having a certain satisfaction at the difficulties into which another has got, we should feel that, if ‘one member suffer, all the members suffer with it,’ and should be ready to help all our fellow-soldiers who need help. Self-preservation as well as comradeship, and, above all, loyalty to Him for whom we fight, should lead to that. Alexander Maclaren, 1826-1910, British Baptist expository preacher

Be of good courage, and let us be strong (to fight) for our people and for the cities of our God. 2 Samuel 10:12a

We create the world in which we live; if that world becomes unfit.; it is because we tire of our responsibility. Cyril Connolly, Enemies of Promise, 1938

(After encouraging the soldiers to fight bravely for their people, Joab said) And may the Lord do what is good in His sight. 2 Samuel 10:12b

Let us fight as if it all depended upon us, but let us look up and know that all depends upon him. Charles Haddon Spurgeon, 1834-92, British Reformed Baptist, highly influential amongst Christians of different denominations

(Israel) drew near for the battle against the Syrians, and they fled. When the people of Ammon saw that the Syrians were fleeing, they also fled. 2 Samuel 10:13,14a

Resolved conviction is a mighty and fearful face to the enemy.