2 Kings 15:12

Thy sons shall sit on the throne of Israel unto the fourth generation— God had promised Jehu, that for executing his will upon the house of Ahab, he would continue the crown of Israel in his family for four generations; and accordingly Jehoahaz, Joash, Jehoram, and Zechariah succeed him; but because he did it not so much in obedience to the divine commands, as to satisfy his private ambition, and in a method of cruelty quite abhorrent to the divine nature, God cut his family short as soon as he had fulfilled his promise to him, and thereby accomplished the prophesy of Hosea: I will avenge the blood Jezreel upon the house of Jehu, and will cause to cease the kingdom of the house of Israel, chap. 2 Kings 1:4. And perhaps it was in remembrance of this promise, as well as of the prophesy which confined the kingdom to Jehu's family for four generations only, that Shallum was encouraged to attempt the life of Zechariah.