Imminency describes an event possible any day, impossible no day. This is also the reason why John was on the island of Patmos, v9, because of the word of God and the testimony of Jesus. Following on from verse 1 in which we are told that the Revelation proceeds from God, we are told here that it is the word of God as well as the testimony of Jesus Christ, this is no product of man's mind, it has the highest claim to be the word of God of any book in the bible. We should not therefore place the book on one side because it is difficult to understand, it has a message that is very important for the saints. He saw the word of God, this gives us one of the keys to understand the book, i.e. he saw the word of God which is to be understood in the light of the rest of the word of God.
Revelation is the last book in the bible, both last in place and last to be written.
It requires all of the earlier sections of the bible, and indeed Revelation, for its interpretation. The Lord, the God of the spirits of the prophets, sent his angel to show his servants the things that must soon take place'. The point of this is to confirm time and time again with the highest authority that these things are true because God's servants need to be prepared to die for their faith, the truth of these words is of supreme importance. If there is no new heaven and no new earth and no lake of fire then why bother to die for ones faith. This is the first of 7 blessings in the book.