I think that we who have come from a religion that says its teachings are based on the Bible, and teaches that it is the word of god and inerrant, are approaching this from the wrong end of the telescope.
Long before there was a (Christian) Bible, before any sort of canon of Christian writings, there was a vibrant, powerful, living faith, a faith that was spreading throughout the Roman Empire, not just because of the efforts of Paul of Tarsus, but spreading before his conversion, and beyond his sphere of influence after his ministry started.
That faith did not spring from, nor depend upon, any "New Testament" writings.
Just as we would have a workable and accepted Theory of Evolution without the fossil record, we would have a christian faith without the N.T
Without the N.T it might not have survived until the 21st century, but I rather think it would have.
The religion came first, the writings later, as with Islam.