2 Samuel 10:12 - Joseph Benson’s Commentary on the Old and New Testaments

Be of good courage, &c. These words, it is likely, were not spoken to Abishai alone, but to all the army by their officers, that they might not be disheartened at the sight of such numerous forces as in a manner encompassed them, but be so much the more resolute for the preservation of their country. And the Lord do that which seemeth him good If they did their duty, he trusted Divine Providence would favour them. But if not, he would be resigned to God's will: he would piously leave the issue with him. And when we have done our part, according to the duty of our place, we may, with the greatest satisfaction, leave the event with God; not thinking that our efforts bind him to prosper us, but that he may still do as he pleaseth, and yet hoping for his salvation in his own way and time.