There the people of Israel were defeated by David’s servants, and the slaughter was great that day—twenty thousand men.
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
Where the people of Israel were slain before the servants of David,.... That is, the people of Israel that were under Absalom, these were beaten by David's army: and there was a great slaughter that day of twenty thousand men; including both those that fell in the field of battle, and that were slain in the pursuit; and this is to be understood only of Absalom's party.
the people of Israel were slain--This designation, together with the immense slaughter mentioned later, shows the large extent to which the people were enlisted in this unhappy civil contest.