Hadadezer ruled in an area more than one hundred kilometres to the north of the Sea of Galilee.1 Saul had fought against the kings of Zobah earlier (1 Samuel 14:47). Presumably they were seeking to extend their influence over Israel in some way and David sought to prevent this.
3 David also defeated Hadadezer the son of Rehob, king of Zobah, as he went to restore his power at the river Euphrates.