Matthew Poole and continuators on Psalms 89:29

29 His seed also will I make to endure for ever , and his throne as the days of heaven .

i. e. To sit upon the Throne for ever, as the next words explain it. This was accomplished onely in Christ, the eternal King of the Church, and of the World, who was of Davids Seed according to the flesh.

i. e. For ever, as he now said, as long as the World shall have a being. It shall be as unchangeable and durable as the Heavens themselves, which are of an incorruptible nature. See the like expression, Deut. 11. 21. Ier. 31. 35, 36.