Thy seed will I establish for ever - Thy children; thy posterity. The reference is to his successors on the throne. The promise was that there should not fail to be one on his throne; that is, that his dynasty should never become extinct. See 2 Samuel 7:16 : “And thy house and thy kingdom shall be established forever before thee: thy throne shall be established forever.” Compare also 1 Kings 2:4. The word rendered “establish” means properly to fit; then, to make firm; to put on a solid basis.
And build up thy throne - It shall be kept up; it shall be like a building that is constantly progressing toward completion. The meaning is, that it would not fail. He would not begin the work, and then abandon it. The dynasty, the kingdom, the throne, would be complete and perpetual.
To all generations - As long as the world should stand. This can have been accomplished only by the Messiah occupying in a spiritual sense the throne of “his father David.” Compare Luke 1:32-33.