One author believes that Revelation 21 is organized in symmetrical form, as a chiasmus:
The seventh and final vision begins in this chapter and concludes in chapter 22. The war is won, the vanquished are removed, and the reward is bestowed upon the conquerers.
21:1-4. In the place of the old universe appears an entirely new one, with God’s dwelling. The new Jerusalem is from God and prepared by him for himself. The image of the bride comes from the OT, as does the language about God residing among men. With the old age the pains and trials have also ceased to exist.
21:5-8. The renewal of all things is the deed of the one seated on the throne (5), who may well be both God and his Lamb (v. 22). He announces the renewal and orders John to write it down, for this is the great revelation in which suffering Christians may rejoice. His declaration, “It is done!” indicates the certainty of his deed, echoing the words of Christ on the cross. Because of who he is, he is able to quench the thirst of the weary and bestow the inheritance of his presence upon the faithful (6-7). With every promise comes a warning. At the head of the list of those whose place is in the lake of sulphurous fire are the cowards, who quail before the threats of the Roman Empire. The second death is final, eternal, definitive, far from God’s presence.
21:9-14. Both punishment and reward come from the same hand. The angel who meted out the seven plagues also introduces John to the wife of the Lamb, which is the holy city of the new Jerusalem. Because God is there, it possesses his glory (11). If at the Fall, a cherubim kept man away from the garden, here twelve angels stand as guards at the twelve gates as protection for God’s people (12). The number 12 stands for the people of God, as the twelve tribes of the nation of Israel and the twelve apostles attest. The three gates on each side of the city recall the distribution of the twelve tribes around the tabernacle when acamped in the desert.
21:15-21. The measurement of the city, its foundation stones, and its walls indicates its perfection. The description of the foundations, decorated with every kind of precious stone, highlight its beauty and preciousness. Though the measurements and descriptions, are hard to visualize – whoever saw transparent gold or a single pearl large enough to form a city gate? –, they are meant not so much as pictures but figures. Revelation is not a visual book, but an associative unveiling, as it ties themes, metaphors, and concepts together for its powerful message of hope and faith. It lays down a series of metaphors to cushion the harsh treatment received at the hands of the imperial government.
21:22-26. Also missing from this city, conspicuously so, is a temple. Both the tabernacle and the temple served as places where God made himself present in the midst of the people. But, now, a temple is rendered unnecessary because God himself and his Lamb are present. Though John sees a vision, it describes the reality of heavenly existence, more real and more precious than the first Jerusalem and the physical temple, which, by this writing, had been destroyed. It is the “land of fadeless day,” where shines the effulgent and constant glory of God. With the banishment of night, there is no need to close the gates to protect its inhabitants, as was done in earthly cities. An unceasing stream of regal glory enters, but never any unclean thing to spoil its beauty and purity, only those whose names are written in the Lamb’s book of life. They are guaranteed that the might of Rome cannot follow them nor disturb their true home. Even the power and wealth of the nations will be subservient to the All-Powerful.