What does Revelation promise to those who read it?
Revelation promises a special blessing to those who read it, hear it, and keep what is written in it, because the time of its fulfillment is near.
Revelation opens with a promise attached to its very reading. In Revelation 1:3 it says, "Blessed is he that readeth, and they that hear the words of this prophecy, and keep those things which are written therein: for the time is at hand." This shows that reading Revelation is not meant to bring fear or confusion, but blessing, especially to those who take the words seriously enough to hold onto them and live by them.
This promise is tied to the fact that the revelation concerns things which must shortly come to pass, events surrounding Christ's judgment, return, and reign. Because the time is at hand, those who read, hear, and keep its words are considered blessed, since they are being prepared and made aware of what God is about to do on the earth.
The scriptures
The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; and he sent and signified it by his angel unto his servant John: Who bare record of the word of God, and of the testimony of Jesus Christ, and of all things that he saw. Blessed is he that readeth, and they that hear the words of this prophecy, and keep those things which are written therein: for the time is at hand.
From the books
This answer is drawn from these passages in the Mary Banks Faith Library.