As you read chapter 10, keep in mind this description of Ahab: “There was never a man like Ahab, who sold himself to do evil in the eyes of the Lord, urged on by Jezebel his wife. He behaved in the vilest manner by going after idols, like the Amorites the Lord drove out before Israel” (2 Kings 21:25-26).
Also remember these words spoken by Elijah to Ahab: “because you have sold yourself to do evil in the eyes of the Lord, [He will] consume your descendants and cut off from Ahab every last male in Israel—slave or free.
Chapter 10 is the fulfillment of this promise (note the specific reference to this fulfillment in verses 10 & 17). Ahab has been dead for fourteen years. God is not always fast regarding his promises, but His promises are always sure. The “sons of Ahab” may not all be “sons,” but rather are likely descendants of Ahab. Because of their lineage, they would all have some claim to the throne.
On the surface, Jehu seems zealous for God. In reality, he is but a blunt instrument of divine retribution. God gave him the monarchy of Israel. He sought to secure it by massacring the house of Ahab. Here, as sometimes happen, things get complicated. God occasionally chooses a person not because he will follow the Lord, but because God knows his heart and will do what God wants done.
What’s the difference? You see it in the life of Jehu. God wanted the descendants of Ahab killed. Jehu would do that. But one should not suppose that Jehu’s actions were carried out with God’s approval. Hosea will condemn Jehu for the massacre at Jezreel (see Hosea 1:4).
It is one of many texts pointing out the sovereignty of God. The Lord will have his way, but just because God’s way gets done doesn’t mean God’s approval. God wanted Saul removed from the throne, but David could not take Saul’s life. Jehu was given the monarchy of Israel, but his job was not to secure it against all opposition. He was to trust the Lord for longevity. He did not. We must be careful in keeping the will of the Lord. Not all of God’s will is ours to keep. The main thing is to do what Jehu did not: to keep the law of God with all our heart (2 Kings 10:31). Killing the sons of Ahab might have been the will of God, but it was not the law of God for Jehu to do it.