2 Samuel 8:3

David smote also Hadadezer, the son of Rehob, king of Zobah, as he went to recover his border at the river Euphrates.

2 Samuel 8:3 belongs to the account of David's victories after he became king over all Israel, when he defeated his surrounding enemies and greatly extended the boundaries of his kingdom to its broadest dominion. It describes David defeating Hadadezer, also called Hadarezer, the son of Rehob, king of Zobah or Zoba, as he went to recover his border at the Euphrates, extending Israel's frontier eastward, and Zoba's territory lay northeast of Damascus between the Orontes and the Euphrates. The events of the chapter are connected with the war described in chapter 10, and these were defensive wars.

Assyria's decline at the time left room for Israel's kingdom to expand to the Euphrates. By the close of these wars David ruled from the river of Egypt to the Euphrates, fulfilling the territory promised to Abraham. The victories gave David rest from his surrounding enemies, which allowed him to consider building a permanent house for God. The house David had in mind was the tent he had pitched for the ark, since the tabernacle itself remained at Gibeon.

The related report of capturing seven hundred horsemen from Hadadezer means seven hundred companies of ten horsemen each, equal to seven thousand individual horsemen in all. Any difference not resolved in this way comes from careless transcribers. This expansion was part of David's military success and prosperity before his sin with Bathsheba, and his rise in power and ease is connected with the circumstances in which he was tempted and fell.