fourth generation. See 2 Kings 15:12. These were Jehoahaz, Joash, Jeroboam II, and Zachariah. Jehu's dynasty was the longest in all Israel.
Related Commentaries of 2 Kings 10:30
2 Kings 10:30
30 And the LORD said unto Jehu, Because thou hast done well in executing that which is right in mine eyes, and hast done unto the house of Ahab according to all that was in mine heart, thy children of the fourth generation shall sit on the throne of Israel.