And it shall come to pass, that him that escapeth the sword of Hazael shall Jehu slay: and him that escapeth from the sword of Jehu shall Elisha slay.

Wesley's Notes

19:17 Shall Elisha slay - One or other of these should infallibly execute God's judgments upon the apostate Israelites. Elisha is said to slay them, either, because he slew those forty two children, 2Kings 2:24, besides others whom upon like occasions he might destroy; or, because he by God's appointment inflicted the famine, 2Kings 8:1, or rather, by the sword which came out of his mouth: the prophets being said to pull down and to destroy what they declare and foretel shall be pulled down. Hazael began to slay them before Jehu was king, though his cruelty was much increased afterward. Jehu destroyed those whom Hazael did not, as king Joram himself, and Ahaziah, and all the near relations of Ahab.

Matthew Henry's Concise Commentary

19:14-18 God repeated the question, What doest thou here? Then he complained of his discouragement; and whither should God's prophets go with their complaints of that kind, but to their Master? The Lord gave him an answer. He declares that the wicked house of Ahab shall be rooted out, that the people of Israel shall be punished for their sins; and he shows that Elijah was not left alone as he had supposed, and also that a helper should at once be raised up for him. Thus all his complaints are answered and provided for. God's faithful ones are often his hidden ones, Ps 83:3, and the visible church is scarcely to be seen: the wheat is lost in chaff, and the gold in dross, till the sifting, refining, separating day comes. The Lord knows them that are his, though we do not; he sees in secret. When we come to heaven we shall miss many whom we thought to have met there; we shall meet many whom we little thought to have met there. God's love often proves larger than man's charity, and far more extended.