What does Revelation chapter 21 mean?
From the time described midway through Genesis chapter 3 until the events of Revelation 20, earth experienced—is experiencing—the presence of sin and death. At the end of chapter 20, John sees God delivering the final and ultimate judgment on Satan, casting all evil into the lake of fire. At that point, creation will finally be free from everything wicked, and what follows is a description of a remade, restored earth.Following the great white throne judgment of chapter 20, John sees a new heaven and a new earth. Scholars debate whether this means that all of creation will be destroyed and re-made, or that God will re-condition creation. The terminology used seems to suggest a renewal. John sees the new city of Jerusalem descending onto the earth, and voices celebrating the restored relationship between God and man. In particular, John hears the voice from the throne declare an end to suffering, pain, and death for all of eternity. At the same time, John hears a reminder that sin, and those who chose it over God, are condemned to the "second death" of hell (Revelation 21:1–8).
John attempts to describe the New Jerusalem in terms others can understand. In doing so, he mentions precious materials such as gold and jasper, but associates them with properties those materials don't normally have. Gold, for instance, is not normally "clear," and neither is jasper. This is John's struggle in explaining what he sees; a modern person might say they saw smoke that looked like "transparent lead," and those hearing it would understand the mixture of two separate ideas. Here, John does something similar in his effort to describe the indescribable (Revelation 21:9–21).
John also points out that there is no temple in this new city, since there is no need for a temple. Temples, priests, and rituals are all necessary when man is somehow separated from God. Two people speaking face-to-face don't need telephones or letters; those living in direct communion with God won't need a temple. This description also re-emphasizes the perfect holiness of this New Jerusalem, and the fact that only those who put their faith in Christ will be found there (Revelation 21:22–27). Revelation 22 is the final chapter of the New Testament. There, John will complete his description of the New Jerusalem and give some final words to those who read this text.