In fact, it is impossible to separate the Scriptures from the early church's work, under the guidance of the Holy Spirit, by which they came to be. I recall a student once asking me to work with him on an independent study. His stated goal was to "get behind the early church fathers, so one could hear the words of scripture alone." My response was that I could not see how we could do that. How do you get behind the work of the early church when it was the early church itself that identified what constituted the Christian Scriptures? Further, it would see quite strange to affirm that God had guided the early church to correctly identify the books (which we affirm when we speak of the Bible as God's word), but not to affirm that God equally guided their judgments about what the Bible meant. To recognize all this should in no way undermine our confidence in the Scriptures, but it should elevate our appreciation for the early church and God's work in guiding it. Were the Scriptures inspired by God? Absolutely, they were inspired to be authoritative regarding the life of faith. Perhaps, though, we would do well to imitate the early church, which affirmed the unique place of the Scriptures as God's inspired revelation without feeling it necessary to say definitively how they were inspired. We have been left free to form our own views of the mechanics.

The first time that the 27 books currently taken to constitute the New Testament show up, all together in an authoritative statement, is in the Festal Letter of Athanasius in the year 367 AD.  Many are surprised to hear that the Christian church had been functioning for nearly four centuries before the final form of the New Testament was settled. Here is how Athanasius put it  (just before this quote, he had listed the Old Testament books):

Continuing, I must without hesitation mention the Scriptures of the New Testament; they are the following: the four  according to Matthew, Mark, Luke, and John, after them the  of the Apostles and the seven so-called  epistles of the apostles—namely, one of James, two of Peter, then three of John and after these one of Jude. In addition there are  epistles of the apostle Paul written in the following order: the first to the Romans, then two to the Corinthians and then after these the one to the Galatians, following it the one to the Ephesians, thereafter the one to the Philippians and the one to the Colossians and two to the Thessalonians and the epistle to the Hebrews and then immediately two to Timothy, one to Titus and lastly the one to Philemon. Yet further the Revelation of John.

Regarding the role of these scriptures, along with those of the Old Testament, Athanasius leaves no doubt:

These are the springs of salvation, in order that he who is thirsty may fully refresh himself with the words contained in them. In them alone is the doctrine of piety proclaimed. Let no one add anything to them or take anything away from them.

He does not stop with this list of texts, but goes on to recognize the importance of certain other writings to salvation and the life of faith:

But for the sake of greater accuracy I add, being constrained to write, that there are also other books besides these, which have not indeed been put in the canon, but have been appointed by the Fathers as reading-matter for those who have just come forward and which to be instructed in the doctrine of piety...