Then David mustered the men who were with him and set over them commanders of thousands and commanders of hundreds.
Which way David raised an army here, and what reinforcements were sent him, we are not told; many, it is likely, from all the coasts of Israel, at least from the neighbouring tribes, came in to his assistance, so that, by degrees, he was able to make head against Absalom, as Ahithophel foresaw. Now here we have, I. His army numbered and marshalled, Sa2 18:1, Sa2 18:2.
Commenting on 2 Samuel 18:1-8
And David numbered the people that were with him,.... Which Josephus says (d) were four thousand; but one would think there should be more by what follows: and set captains of thousands and captains of hundreds over them; he divided his army into companies, which consisted some of a thousand and others of a hundred; over each of which he set captains, to lead them...
And David numbered the people that [were] with him, and set captains of thousands and captains of hundreds over them. (a) For certain of the Reubenites, Gadites, and of the half tribe could not bear the insolence of the son against the father, and therefore joined with David.