It seems to me that there are a number of reasons to accept and trust the NT documents as we have them even before we introduce notions of scripture and canon:
- Firstly, it is indisputable that the reconstructed documents that we have correspond almost exactly and in a very precise way to the original documents written. The science of textual criticism has, because of the unprecedented number and quality of the extant copies the NT documents, has allowed us to reconstruct them with remarkable accuracy. The NT we read today is absolutely trustworthy in this regard.
- Secondly, earlier scepticism with regard to early dating of the NT documents has been assuaged and it is now generally felt by most scholars that they are all relatively early. This gives us confidence that they correspond, in the way that they claim, to the teachings of the apostles.
- With regard to the Gospels and Acts, modern scholarly study is (slowly) recovering from the biases of the liberal scholarship of the past few centuries and is rediscovering that the gospels have all of the hallmarks of being well-researched eye-witness accounts. It is becoming increasingly clear, from a scholarly perspective, that they are largely trustworthy as historical documents. This may not yet be the consensus but the liberal dismissal of the historicity of the Gospels and Acts has been seriously and convincingly challenged. For scholars who reject the presuppositions of liberalism (many of which were pre-scholarly biases disguising themselves as scholarly scepticism) the historical documents of the NT have been found to be much more trustworthy than once thought. Moreover, much of this work is being done by non-evangelical scholars. As such, even from a simplistic pre-faith point of view, it seems reasonable to accept the Gospels and Acts as reliable historical documents (in they way we would accept other similar early histories). Even without positing a doctrine of scripture or of canon we, as Jesus followers, will be interested to read these documents to learn about Jesus and his teaching and to learn about the practices of the apostles and early churches. This, one must remember, will have been their original purpose. See, for instance, the introduction that Luke writes to his gospel.
- With regard to the Pauline epistles it is beyond dispute that many of the letters that bear his name were written by him. Even many of those letters that were previously thought to be inauthentic are now being reconsidered and found to be genuine. Paul was an important and influential early believer and so we will want to read his writings even before we have decided they are scripture. Moreover, Paul argues convincingly for his points and argues that they themselves are inspired by the Spirit and are truth (without reference to a notion of scripture). We can read them, think on them, and find them convincing.
- The same holds for the other epistles. Even in cases where they may not have been written by those whose names they bear they were all composed so early as to almost certainly correspond to apostolic teaching. The general unity of teaching in the NT would seem to back this up. Thus if we, as the early believers did, wish to hold fast to the teachings of the apostles we will eagerly read them even if we have not formulated a doctrine of canon or of NT scripture.
- The Revelation of John claims, in a manner similar to the OT prophets, to be a record of prophecy. In fact, John claims he was told to record the prophecy by Jesus himself. There is even a command not to alter the words of the prophecy or add to it. Thus, the Revelation demands to be read as scripture. So, apart from any considerations involving other NT documents, this book must be read as scripture or not at all. We must choose to accept it, as we choose to accept other scripture, or choose to reject it entirely. It has a different status from the other NT books, which mostly do not claim to be written scripture (even when they claim to be true) and where the authors do not appear to be conscious of writing scripture.