Every single book and letter, in the Bible, is relevant to the church throughout history. We may not think so, or understand how portions of certain books are relative, but they are.

Modern church teachings would have Revelation to be an absolutely un-relative letter to the church. The modern teaching of Revelation being fulfilled during a
seven-year tribulation period at the coming end of Earth, and the church being raptured out before this time, has this letter completely useless in modern day.

“Write on a scroll what you see and send it to the seven churches: to Ephesus, Smyrna, Pergamum, Thyatira, Sardis, Philadelphia and Laodicea.” (Revelation 1:11)

What is the purpose of the letter of Revelation? The primary purpose of Revelation was to bring hope to a first-century church of Asia minor that was experiencing persecution and wondering if it's worth it. This letter is apocalyptic literature that uses imagery to bring hope. That's the purpose of apocalyptic literature.

Revelation chapter 1 tells us
who this book was intended for. It's this book that also has a warning for those who adds to the writings (Revelation 22:18). Therefore, anyone who teaches this book needs to make sure they keep the teaching as close to it's original intent and not just repeat what they've heard or been taught that contradicts what we're being told in the book itself.

Revelation is sandwiched by the statements, "
what must soon take place" (1:1) and "the time is near" (22:11). John was not mistaken on this as it was an angel from the Father who told John this. Thus, the times which are warned about in Revelation was near to the first-century church it was written to.

Revelation was written to and its images, and events revolved around, the first-century churches in Asia Minor who was being persecuted by the Roman Empire; and people who are literally running for their lives. DON'T TURN THIS OFF JUST YET. The most popular teaching comes from a book that has been changed and reproduced four times:
Dispensational Truth. How would you feel if your paycheck was short four times real quick? You'd question the abilities of, or integrity of, your employer. Why would we treat the errors in this book any different. It's obvious there's an issue with the information being transmitted.

Write therefore the things that you have seen, those that are and those that are to take place after this. Revelation 1:19

While the letter of Revelation was written to a first-century church, it's applicable to churches throughout time and has a message for each and every church age until the end. Even though it includes churches of all ages, the imagery,
remez's, and cultural notations used are those from the first-century understanding. We need to make sure we know how to study Revelation.