For the writers of the New Testament, including our earliest author, Paul, the “scriptures” referred to the Jewish Bible, the collection of books that God had given his people and that predicted the coming of the Messiah, Jesus. It was not long, however, before Christians began accepting other writings as standing on a par with the Jewish scriptures. This acceptance may have had its roots in the authoritative teaching of Jesus himself, as his followers took his interpretation of scripture to be equal in authority to the words of scripture itself.
