2 Samuel 10:17

David … gathered all Israel together. Some commentators see in this an indication of dissatisfaction with Joab. Really it was a matter of course that in so great a war the king should place himself at the head of his levies. For not only was he possessed of great military genius, but his personal presence would make the men of Israel, a race of sturdy free men, assemble in greater numbers, and would give them confidence. If David himself went there would be no shirking the war and finding excuses to stay at home, and in the camp there would be prompt alacrity and zeal.