Revelation, according to me, is the most unique book in the Bible.
John is the author, who, if you know anything about him, was one of the disciples of Jesus. He wrote the books of John, 1 John, 2 John, and 3 John.
But this book is his weirdest.
So, he has been exiled to an island called Patmos, and he is writing to 7 churches in Asia Minor.
Besically he is outlining to these churches
He encourages them to stand firm and to stick with Jesus. Each church gets what is like a report card with positives and negatives. But the bottom line is : Stick to Jesus.
The powers of darkness get their glory in the sun. John warns the believers that at times it looks like they are somewhat winning. But this is the way of the believers, that we conquer through the way of the cross, through persecution.
Ultimately we see who wins and what will happen, so there is nothing to be afraid of for the believer.