Charles Ellicott Commentary 2 Samuel 18:7

"And the people of Israel were smitten there before the servants of David, and there was a great slaughter there that day of twenty thousand men." — 2 Samuel 18:7 (ASV)

Twenty Thousand. —This number seems large, but we really know nothing of the size of the forces engaged on either side; and if the phrase “that day” is taken, as often, broadly enough to include the whole campaign of which this battle was the culmination, there is nothing surprising in the destruction of 20,000 men. Of the human causes of the victory nothing is told. We may assume that the advantage of thorough military organization and generalship was on David’s side; but, in addition to this, was the vast power of the right, the prestige of law and authority.