If its basis isn't solely on the Bible alone, maybe it should be.
In the originals, each and every word was crafted and placed there by God, not man, and its truth/doctrines therefore timeless for all who read it irrespective of external factors. If not perceived, understood and trusted on that basis - that it is self-contained - its own dictionary, glossary, cross-reference, and instruction manual, etc., its rules of interpretation become meaningless, and it then becomes just another historical book - and I'm surprised that you don't already see it that way given you're as knowledgeable in the Bible as you are.
Not to get into a never-ending debate with you over this (as I don't have the energy and patience for that anymore), but what do you think God meant by the following verses? Has He ever referenced any book, or anything else, outside of scripture telling us that it too is able to make the man of God perfect and thoroughly furnished unto all good works? Do you that think God didn't realize what He was saying by that, or is it that you think He isn't to be trusted?
16 All scripture [is] given by inspiration of God, and [is] profitable for doctrine, for reproof, for correction, for instruction in righteousness:
17 That the man of God may be perfect, throughly furnished unto all good works.