Revelation 21:1

We have here a more general account of the happiness of the church of God in the future state, by which it seems most safe to understand the heavenly state. I. A new world now opens to our view (Rev 21:1): I saw a new heaven and a new earth; that is, a new universe; for we suppose the world to be made up of heaven and earth. By the new earth we may understand a new state for the bodies of men, as well as a heaven for their souls. This world is not now newly created, but newly opened, and filled with all those who were the heirs of it. The new heaven and the new earth will not then be distinct; the very earth of the saints, their glorified bodies, will now be spiritual and heavenly, and suited to those pure and bright mansions. To make way for the commencement of this new world, the old world, with all its troubles and commotions, passed away. II. In this new world the apostle saw the holy city, the new Jerusalem, coming down from heaven, not locally, but as to its original: this new Jerusalem is the church of God in its new and perfect state, prepared as a bride adorned for her husband, beautified with all perfection of wisdom and holiness, meet for the full fruition of the Lord Jesus Christ in glory. III.

— Matthew Henry's Concise Commentary (public domain)