Hadezaer was the king of Zobah and enemy of David. When the kingdom of Israel was firmly in David’s control, he began to branch out beyond his borders and defeat enemy nations, including the Philistines and the Moabites. It seems that the Ammonites became nervous at David’s victories and hired troops from the neighboring Aramean nations to fight him.
King Hadadezer of Zobah, a kingdom to the north of Israel, must have been among them. When David defeated them, Hadadezer regrouped and called upon even more troops from his vassals (subservient kingdoms) in the far north, but David defeated them as well. This caused Hadadezer’s vassals to abandon their loyalty to him, and he was forced to march his troops to their lands to reestablish control over them. In the meantime, David invaded Zobah itself and captured Hadadezer’s kingdom (2 Samuel 10).
David took a large quantity of bronze from some of Hadadezer’s towns, and Solomon used this to create some of the bronze articles for the temple (1 Chronicles 18:8). David’s victory over Hadadezer must have been very impressive, because the king of Hamath, just north of Hadadezer’s territory, sent his son to congratulate David on his victory, and he gave him gifts of silver, gold, and bronze (2 Samuel 8:9–10).
The king of Hamath had also been at war with Hadadezer.