Chapter twenty-two reveals the final details given to us about the future and end of all things. The tree of life that was in Genesis 2 reappears in the eternal state (Revelation 22:2). What is meant by its leaves being “for the healing of the nations” is highly debated and unclear.
Unlike twice before, where Daniel (Daniel 12:4, 9) and John (Revelation 10:4) were required to seal up what they saw and heard, John was specifically commanded now to “not seal up the words of the prophecy contained in this book” (Revelation 22:10). The final verses contain a series of blessings on those who believe in the prophecy and act on it by believing in the Lamb, much like the blessing in Revelation 1:3 on those who obey it.
A curse is pronounced on all who would change the prophecy, because to do so would be to make God out to be a liar (Revelation 22:18-19), because it came from Jesus himself (Revelation 22:16). This prophecy is essentially history written in advance, as John used the past tense throughout to record what he already saw take place. To change the record would be as effective as trying to change history.
The final promise from Jesus is that he is coming soon. Anyone who has believed in him can say with John, “Amen! Come, Lord Jesus!” (Revelation 22:20)