And thou shalt cut off the house of Achab thy master, and I will revenge the blood of my servants the prophets, and the blood of all the servants of the Lord at the hand of Jezabel.

and thou hast smitten the house of Ahab thy lord, and I have required the blood of My servants the prophets, and the blood of all the servants of Jehovah, from the hand of Jezebel;

You are to see that the family of Ahab your master is cut off, so that I may take from Jezebel payment for the blood of my servants the prophets, and for the blood of all the servants of the Lord.

Thou shalt smite the house of Ahab - For their most cruel murders they have forfeited their own lives, according to that immutable law, "He that sheddeth man's blood by man shall his blood be shed." This and the two following verses contain the commission which Jehu received from the Lord against the bloody house of Ahab.

And thou shalt smite the house of Ahab thy master,.... For Jehu was one of Ahab's captains, as he was now one of his son's, as appears from 2-Kings 9:25, but this was to be no objection with him to the destroying of his house, as being an act of high treason, since he had an order for it from the King of kings, and Lord of lords; which otherwise would have seemed unlawful and criminal, and what follows will sufficiently vindicate the justice of God in it:
that I may avenge the blood of my servants the prophets, and the blood of all the servants of the Lord, at the hand of Jezebel; who killed the prophets of the Lord, and caused to be put to death Naboth the servant of the Lord, and now their blood was to be avenged on her and her son Joram, and all her family.

I may avenge,&c. - That they were idolaters was bad enough: yet that is not mentioned here: the controversy God has with them, is for being persecutors. Nothing fills the measure of the iniquity of any prince so as this doth, nor brings a surer or sorer ruin.