And he said to me, "THESE WORDS are FAITHFUL and TRUE";
The angel who was directed to show John the eternal new Jerusalem, new heaven, and new earth (Revelation 21:9 and Revelation 22:1) tells John, again, that what John has written is FAITHFUL and TRUE. This angel can say this because he is a presence angel with very close contact with God and the LAMB. John on the other hand must be mind boggled by all the judgments and visions he has been taken through. There words must be comforting to him.
Note that while in the broad sense, the whole of the Revelation is FAITHFUL and TRUE (and a person could argue the same for the whole Bible (2 Timothy 3:10-16-17), the specific passage about the new heaven, new earth, and new Jerusalem were prefaced with these same FAITHFUL and TRUE words (Revelation 21:5). What is implied here is that a person doesn't have the prerogative to pick and chose those parts of THESE WORDS they wish to believe are FAITHFUL and TRUE. God has made that choice already.
and the LORD, the GOD of the spirits of the PROPHETS, sent His angel to show to His BOND-SERVANTS the things which must shortly take place.
If this phrase sounds vaguely familiar, it is because the book of the Revelation started out this way (Revelation 1:1-3).
The angel confirms that John, indeed, is in a long line of prophets. It is no accident that there are many cross references to Daniel, Ezekiel, Isaiah, Joel, Zechariah, Micah, Zephaniah, and other prophets throughout this study. Indirectly implied here, however, is that when the eternal CITY, new heaven and new earth are established, prophesy will cease. There is no need for prophesy (2 Peter 1:12-20-21). Furthermore, with the church disbanded by now, there is no need 'to edify the church' through prophesy (1 Corinthians 14:1-25).
Today, we don't see the events taking place in the Revelation as 'taking place shortly'. That is our restriction inasmuch we live in such a short time span compared to eternity. To the eternal LORD, the GOD of the spirits of the PROPHETS, all prophesy and Revelation would appear to take place shortly. However, note, there are no options here.