Here is an excerpt from The Scandal of the Charismatic Mind II on the importance of the Bible to Christianity:
As I have remarked elsewhere, in spite of the many expressions and differences, the Bible has been germane if not fundamental to historic Christian faith. From the onset what we know today as the Bible was absolutely essential to the early Jesus movement which eventually became known as Christianity. Contrary to popular perceptions about what religion is supposed to look like, this was very odd in the ancient world where Christianity arose. The vast majority of ‘religions’ throughout human history do not have sacred scriptures, let alone anything like the Bible. For instance the central claim of Christianity is not only that God rose Jesus from the dead but it all happened according to the scriptures (1 Corinthians 15:3-4.) Christian faith cannot exist apart from the Bible.