John Wesley on 2 Kings 8:19

Alway - Until the coming of the Messiah: for so long, and not longer, this succession might seem necessary for the making good of God's promise and covenant made with David. But when the Messiah, was once come, there was no more need of any succession, and the scepter might and did without any inconvenience depart from Judah, and from all the succeeding branches of David's family, because the Messiah was to hold the kingdom forever in his own person, though not in so gross a way as the carnal Jews imagined. A light - A son and successor.