1 Kings 11:25

He was a secret enemy, watching all occasions to do them mischief cunningly and privately all that time; and when Solomon had forsaken God, and was forsaken by God, he showed himself more openly and maliciously. Beside the mischief that Hadad did; so the sense is, this infelicity was added to the former concerning Hadad, mentioned above, 1 Kings 11:14, &c. Whilst Hadad molested him in the south, Rezon threatened him in the north. But some understand this of Hadadezer, who is here called Hadad, by way of abbreviation, (which is not unusual in proper Hebrew names, as is well known,) and that for, or because of, (for the Hebrew particle eth is sometimes put for el, which oft signifies for, or because of, as Hebricians know,) the evil which befell Hadad, or Hadadezer, i.e. he bore a grudge against the Israelites from and ever since the slaughter that Joab made in Hadadezer's army, whereof he was a member, although he also took that occasion of making a defection from his master. Reigned over Syria; over all that part of Syria, enlarging his empire more and more, and thereby laying a foundation for much misery to Solomon's house and kingdom.