2 Kings 9:27

But when Ahaziah the king of Judah saw this, he fled by the way of the garden house. And Jehu followed after him, and said, Smite him also in the chariot. And they did so at the going up to Gur, which is by Ibleam. And he fled to Megiddo, and died there. Ahaziah - was grand-nephew to king Joram, and great-grandson to king Ahab.

Jehu ... said, Smite him also in the chariot. It is remarkable that the vengeance threatened was brought on the house of Ahab at the very time that the king of Judah was on a visit to Joram, that he might partake of the punishment, as being a descendant of the wicked Ahab. It was by an unexpected concurrence of circumstances that this took place. Joram having been wounded in fighting against the Syrians at Ramah, it was providentially ordered that he should go to Jezreel rather than to Samaria, to be healed of his wounds. Thither his relative Ahaziah had come to visit him, while lying disabled in that place. There is no evidence that Jehu fixed on this time from a wish to include the king of Judah in the punishment of Ahab's family. It does not even appear that Jehu was aware of Ahaziah's being then at Jezreel. All was the result of God's immutable purpose, and accomplished by a wonderful operation of His providence.

Ibleam - near Megiddo, in the tribe of Issachar (Joshua 17:11; Judges 1:27), and Gur was an adjoining hill.