2 Kings 9:8 - Joseph Benson’s Commentary on the Old and New Testaments

For the whole house of Ahab shall perish That is, all his posterity and all his kindred. Jehu, therefore, having received such a charge, is to be considered, in what he afterward did to the house of Ahab, as acting not out of a spirit of revenge, for he had no quarrel with the house of Ahab; but, as the minister of God, who, by his prophet, authorized and enjoined him to do what follows.