The Second Essential Thing you Need to Know about the Book of Revelation
Revelation is steeped in the thought and imagery of the Old Testament and is written with the assumption that you will be too. That means that the author is not expecting you to see his quotations and allusions to the Old Testament as “proof texts” but as a complex web of associations which will call up, not just the particular words cited, but the entire context of an image or quote.
Think of it this way. Suppose, in speaking of the odious Dennis Kucinich, I mention that he is “Saruman” or that he is trying to grasp the Ring. I’m not just expecting you to look for a single line out of the Lord of the Rings. I’m expecting you to know all about this once faithful Saruman who sold his soul in order to grasp at power and then to be able to apply that image to Kucinich. Similarly, New Testament writers (and nobody more than St. John the Divine) are expecting you to know the entire context of their allusions to the Old Testament (and to the events of the gospel) so as to apply those contexts to the visions recorded in Revelation. That means that paying attention to the cross references and their full contexts in the Old Testament is not an option. If you aren’t willing to do that, you will not understand what Revelation is getting at.