Revelation 21:1 - 8
ESV - 1 Then I saw a new heaven and a new earth, for the first heaven and the first earth had passed away, and the sea was no more. 2 And I saw the holy city, new Jerusalem, coming down out of heaven from God, prepared as a bride adorned for her husband.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
This Revelation was transmitted
FROM God
►► to Christ,
►► to the angel,
►► to John,
►► to the churches,
►► to us.
The messages to the churches are given immediately after the vision of Christ of Rev. 1. These "things" were to take place from John's day to and including the eternal events of the new heaven and new earth. The events are consecutive in order with parenthetical passages inserted between the main events, which explain certain things that are to happen along with the main events but are not the same as these events. The book has three clearly-defined divisions (Rev. 1:19), the contents of which follow each other in the following order:
1. "The things which thou hast seen," i.e., the vision of Christ in the midst of the candlesticks (Rev. 1:12-20), which, together with the introduction to the whole book forms chapter 1.
2. "The things which are," i.e., the seven letters to the seven churches in Asia Minor, or present Turkey, to whom the whole book is addressed (Rev. 2:1--Rev. 3:22). These messages to the churches apply to the whole church age and until the rapture of the church just before the future tribulation and coming of the Antichrist, who will be here for the last seven years of this age (Dan. 9:27; 2Th. 2:7-12 Rev. 6:1--Rev. 19:21).
3. The things which shall be hereafter," i.e., events after the rapture of the church (Rev. 4:1--Rev. 22:5). These include the scenes in heaven (Rev. 4--Rev. 5), the seven seals and their parenthetical statements (Rev. 14:1--Rev. 19:21), the Millennium (Rev. 20), and the new heaven and new earth (Rev. 21:1--Rev. 22:5), and events of the conclusion (Rev. 22:6-21). If the things of Rev. 4:1 on must be after the things of the churches, then they will not be fulfilled along with the things of the churches. This means that every event of Rev. 4--Rev. 22 must be fulfilled after the rapture of the church. It also means that no historical or present event could possibly be a fulfillment of any event of Rev. 4--Rev. 22.