We are on the same side on this one so this is not a nasty challenge. God has admonished against adding or taking away from his word throughout the OT & the NT. I think it is a mistake to think that the revelation from Jesus to John was solely for the book of revelation and not a reiteration of a constant theme.
You COULD read it so narrowly as to apply only to the book of revelation but IMO it makes much more sense to apply it to the NT as a whole.
Sorry; but using your logic; we'd never have even GOTTEN the NT!
I don’t agree that that interpretation, because firstly, it is specifically referring to “this book of prophecy”. The Revelation is a book of prophecy, while the Bible in it’s entirety cannot be limited to that description. Occam’s razor, in this case, says we should assume it only refers to Revelation and not the less likely scenario.
Secondly, the punishment cited for disobedience mentions the curses contained in the same book. If the book that is referred to is Revelation, then what those curses are is immediately clear, while if the book is the Bible as a whole, then this clause becomes unspecific and, therefore, a much less concrete warning.
Finally, there is the reason I previously cited, that the New Testament wasn’t even a collected work at the time that verse was written, much less with Revelation in its traditional place as the final book in the collection. So, in order to make the warning refer to the Bible, you’d have to assume that the warning was prophetic in order to have it make any sense.
Basically, in all those circumstances, you have to do some logical gymnastics to justify the verse as applying to the Bible. If you don’t have that goal in mind, the plain reading is that it is just referring to Revelation itself.