Revelation is not to be read chronologically. Rather, John uses repetition to emphasize a key theme. Time and again John takes the reader up to the end of the world to drive home the point that when Christ returns he will come in judgment—to reward those who are faithful and punish those who are not. The age-long conflict between God and Satan and their respective followers flows through the book.
There is only one end of the world and only one final coming of Jesus (Hebrews 9:27, 28), and yet John writes about the event at numerous points. For example, each series of seven (the seals in 6:12ff., the trumpets in 11:15ff. and the bowls in 16:17ff.) ends with a description of the final judgment.
We need to be reminded that John stated that the revelation was going to be made known in symbols (1:1 in the King James Version reads that the revelation “was signified,” a word meaning “to make known in symbols”). All colors, animals, numbers, etc. are symbols pointing to spiritual realities and must never be interpreted literally. Revelation is filled with “word pictures” that help us see the inner meaning of spiritual truths. For example, Jesus is not literally a lamb, but the image symbolizes his sacrificial death.
Some interpreters try to have it both ways. They emphasize the symbolic character of the scene in 20:1-3 (a key and chain), but when it comes to the 1,000-year reign, they want to make it literal. They appear to mingle the symbolic and the literal at a mere whim. Those who take the number 1,000 literally pay no regard to the symbolic use of all numbers (seven, twelve, etc.). Not once in Revelation is the number 1,000 used literally. If we interpret the 1,000 years literally in Revelation 20:1ff., it will be the only example of a literal use of numbers in Revelation. But beyond this fatal objection, consider the structure of the paragraphs in Revelation 20.