Here is, 1. A new attempt of the Syrians to recover their lost honour and to check the progress of David's victorious arms. The forces that were lately dispersed rallied again, and gathered themselves together, Sa2 10:15. Even the baffled cause will make head as long as there is any life in it; the enemies of the Son of David do so, Matt, Sa2 22:34; Rev 19:19. These, being conscious of their insufficiency, called in the aid of their allies and dependencies on the other side of the river (Sa2 10:16), and, being thus recruited, they hoped to make their part good against Israel, but they knew not the thoughts of the Lord, for he gathered them as sheaves into the floor; see Mic 4:11-13. 2. The defeat of this attempt by the vigilance and valour of David, who, upon notice of their design, resolved not to stay till they attacked him, but went in person at the head of his army over Jordan (Sa2 10:17), and, in a pitched battle, routed the Syrians (Sa2 10:18), slew 7000 men, who belonged to 700 chariots, and 40,000 other soldiers, horse and foot, as appears by comparing Ch1 19:18. Their general was killed in the battle, and David came home in triumph, no doubt. 3. The consequence of this victory over the Syrians. (1.) David gained several tributaries, Sa2 10:19. The kings, or petty princes, that had been subject to Hadarezer, when they saw how powerful David was, very wisely made peace with Israel, whom they found they could not make war with, and served them, since they were able to give them protection. Thus the promise made to Abraham (Gen 15:18), and repeated to Joshua (Jos 1:4), that the borders of Israel should extend to the river Euphrates, was performed, at length. (2.) The Ammonites lost their old allies: The Syrians feared to help the children of Ammon, not because they had an unrighteous cause (justifying a crime which was a breach of the law of nations), but because they found it was an unsuccessful cause. It is dangerous helping those that have God against them; for, when they fall, their helpers will fall with them.

Jesus Christ, the Son of David, sent his ambassadors, his apostles and ministers, after all his servants the prophets, to the Jewish church and nation; but they treated them shamefully, as Hanun did David's ambassadors, mocked them, abused them, slew them; and it was this that filled the measure of their iniquity, and brought upon them ruin without remedy (Mat 21:35, Mat 21:41, Mat 22:7; compare Ch2 26:16); for Christ takes the affronts and injuries done to his ministers as done to himself and will avenge them accordingly.

The Syrians were fled - They betook themselves to their own confines, while the Ammonites escaped into their own city.

And when the Syrians saw that they were smitten before Israel,.... Considered it in their minds, and conversed with one another about it, and fearing what would be the consequence of it:

they gathered themselves together; not only the forces got together again, that fled before Joab, but all the kings of Syria united their forces together, as appears from Sa2 10:19; supposing that David would avenge himself on them for assisting the Ammonites against him; and therefore judged it advisable to raise a large army, that they might be in a condition to receive him.

So Joab returned and came to Jerusalem--Probably the season was too far advanced for entering on a siege.