(19) Servants to Hadarezer.--The vassal kings, who had been tributary to Hadarezer, now transferred their allegiance to David; but it is not said that Hadarezer himself became a tributary, though it is plain from 2Samuel 8:3-7, that he was greatly weakened and suffered the loss of large booty. From 1Kings 11:23-24, it is plain that an escaped dependent of Hadarezer maintained himself in the territory of Damascus as an enemy of Israel; it is also stated in 1Kings 4:21, that Solomon "reigned over all kingdoms" from the Euphrates to the border of Egypt. It is therefore probable that Hadarezer also acknowledged the suzerainty of David and Solomon.

Verse 19. - The kings... served them. It is evident from this that the petty kings of Rehob, Tob, and Maacah had been subject to Hadarezer; they now acknowledged the supremacy of David, and paid to him the tribute which they had previously paid to Zobah, and would be bound to supply him with a contingent of men in case of a war in their neighbourhood. The wars with Damascus and Edom, mentioned in 2 Samuel 8:5, 13, probably followed immediately upon Hadarezer's defeat, but are not referred to here, as the interest now centres in David's personal conduct.

10:15-19 Here is a new attempt of the Syrians. 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. But now the promise made to Abraham, Ge 15:18, and repeated to Joshua, Jos 1:4, that the borders of Israel should extend to the river Euphrates, was performed. Learn hence, that it is dangerous to help those who have God against them; for when they fall, their helpers will fall with them.And when all the kings that were servants to Hadarezer,.... That were subject to him, and at his beck and command, at least were hired by him into his service:

saw that they were smitten before Israel; could not stand their ground against them, being too powerful for them:

they made peace with Israel, and served them; became tributaries to them, whereby the promise of the land of Canaan made to Abraham and his seed, as reaching to the river Euphrates, had its accomplishment, Genesis 15:18,

so the Syrians feared to help the children of Ammon any more; who standing by themselves, they were soon and easily conquered by David's forces, as recorded in the following chapters.