They gathered themselves together Fearing David would fall upon them for assisting his enemies, they resolved to be beforehand with him, and therefore levied a new army to invade his territories. And Hadarezer Who was king of Aram Zoba, in Mesopotamia; sent and brought out the Syrians that were beyond the river That is, beyond Euphrates, which was the bound of his territories eastward, 2 Samuel 8:3.
Related Commentaries of 2 Samuel 10:15
2 Samuel 10:15-16
15 And when the Syrians saw that they were smitten before Israel, they gathered themselves together.
16 And Hadarezer sent, and brought out the Syrians that were beyond the river:c and they came to Helam; and Shobach the captain of the host of Hadarezer went before them.