Jamieson, Fausset and Brown on 2 Kings 15:8-10

8-10. In the thirty and eighth year of Azariah king of Judah did Zechariah the son of Jeroboam reign over Israel--There was an interregnum from some unknown cause between the reign of Jeroboam and the accession of his son, which lasted, according to some, for ten or twelve years, according to others, for twenty-two years, or more. This prince pursued the religious policy of the calf-worship, and his reign was short, being abruptly terminated by the hand of violence. In his fate was fulfilled the prophecy addressed to Jehu (2Ki 10:30; also Ho 1:4), that his family would possess the throne of Israel for four generations; and accordingly Jehoahaz, Joash, Jehoram, and Zechariah were his successors--but there his dynasty terminated; and perhaps it was the public knowledge of this prediction that prompted the murderous design of Shallum.