The New Jerusalem is a literal city with specific dimensions. It is to be the dwelling place of the bride.
The old covenant Jews are to dwell in the promised land forever.
Two dwelling places suggests to me two classes.
The Vision of the City (21:9-21)
Is one of the seven angels the same angel who showed John the vision of Babylon in chapter 17? There is no way to be sure. The reference to a single angel in 1:1 and 22:16 suggests that it is, yet the angel now plays a somewhat different role. The vision of the holy city, unlike that of Babylon and the beast, is not a cryptogram that needs decoding. Consequently the angel is not an interpreting angel (as in 17:7-18). Instead, John supplies the interpretation himself (21:22-27; 22:3-5).
The angel promises to show John the bride, the wife of the Lamb (v. 9), but what then appears is a city, not a woman (v. 10). From this point on, the bridal imagery is dropped, to surface again only in 22:17. The image of the city as a woman is not carried through consistently, as it was in chapters 17 and 18. The angel shows John the holy city (vv. 9-14) and then measures it (vv. 15-21). The mountain great and high (v. 10) to which John is taken in the Spirit (that is, in his vision) is more than a vantage point from which to view the holy city. It is Mount Zion itself (14:1), on which the city stands, or rather “lands” in its descent from the sky.