Questions concerning the Bible have long surrounded the Christian Faith. What is the Bible? Where did it come from? Who wrote the books that are in Bible? Can we trust that fallible human beings wrote and chose the correct books for canonization? Occasionally, scholars will doubt the historical veracity of Christian Bible based upon its “late” creation, years after the events it purports to recount took place. An important part of understanding the historicity and reliability of the Christian Bible involves understanding the formation of the New Testament, as understanding this history of canonization shed light on the contents and context of the Christian Bible more broadly.
Of course, one cannot discuss the formation of the New Testament without first looking at its predecessor, the Jewish Tanakh, the Christian Old Testament. J. N. D. Kelly wrote that “Judaism was the cradle in which Christianity was nurtured, the source to which it was uniquely indebted.” While some critics argue that the Tanakh wasn’t actually canonized until the Council of Jamnia (c. 100 CE), the majority of what we now call the Jewish Scriptures (such as the Torah and Prophets) were authoritatively accepted and referenced as “scripture” well before the time of Christ. The earliest Christians relied heavily upon the Old Testament for insight, not only for understanding and interpreting Christ’s work, but for practical guidance in the life of the Church as well. It is also worth noting that among the earliest Christian writers there was considerable debate concerning which of the apocryphal books, if any, should be used as authoritative. Such debates aside, Christianity seems to have inherited from Judaism a penchant for using and viewing as authoritative written books.
An oft-forgotten reality is that many of the earliest gatherings of Christians would not have had access to the scriptures—in whole or in part. Those that did have something in the earliest years would have had the Septuagint version of the Old Testament. This eventually would have been supplemented by specifically Christian writings as they were written and circulated among Christian communities; yet for many early Christians there was no “Bible”, only the influence and authority of the orally proclaimed good news of Jesus Christ. Of course, where writings were available it made sense for the Church to simply continue the “Jewish tendency to write and revere authoritative religious books.” Yet while the earliest Christian faith was rooted in the person of Jesus Christ, as time went on it made more sense for Christians to commit the story of Christ to written works. But this was a process, sometimes taking generations for any given community to gain access to even a handful of the writings now included in the New Testament. Given this reality, one can see the importance of having strong Christian leaders who not only possessed faith but also the ability to explain, expound, and defend the Christian message.
As the writings now included in the New Testament began to circulate within (and without) the Greco-Roman world, Christians naturally began to collect them into a “canon.” When referring to the term “canon” (especially of the New Testament) definitions become extremely important. Over the years scholars have gathered themselves into three distinct schools of thought concerning the formation of the “New Testament Canon.” Some, such as Theodor Zahn, argue that since many of the foundational books of the New Testament were regarded as authoritative scripture by the end of the first century—as demonstrated in a text like First Clement—then the canon should be considered an early feature of the faith.
A second perspective, such as that held by Adolph von Harnack, takes a more fluid view of the creation of the canon. Arguing that while the texts included in scripture where written early on in the Christian tradition, they were not regarded as scripture until several decades or even centuries later. For Harnack, the influence of Marcion was very important in pushing the Church to adopt a formal canon of scripture by the late second and early third centuries. For another variation of this view, three heretical influences—Gnoticism, Marcionism, and Montanism—encouraged the Church to formulate and fix certain books with canonized status. A third school of thought concerning canonization relies heavily upon the definition of the word “canon.” A. C. Sundburg maintained that the term ‘scripture’ refers to books commonly accepted as holy and authoritative, whereas the term ‘canon’ refers to an authoritative list of such books. In this view, the canon of the New Testament can only be said to have formed in the fourth century, since that’s when the first authoritative canonical lists began to appear.
Yet despite the apparent differences between these three views on canon formation, John Barton has pointed out that very little has actually been said about the heart of the canon debate, namely, when Christians began to use and view Christian writings as authoritative sources for understanding and living their faith in Christ. While Metzger is correct in pointing out the “difference between a collection of authoritative books and an authoritative collection of books”, canonical scholarship needs to look beyond semantics and determine what was considered authoritative scripture, instead of solely focusing on when the New Testament canon was formulated as a complete set of books. At this point, we must introduction an important semantic distinction, that between “functional” and “formal” canons. A functional canon encompasses Zahn’s claim that Christian writings were used very early on by the Church—a functional canon is simply a reference to a collection of books that are practically authoritative but are not officially deemed so. In contrast a formal canon follows Sundberg’s definition—an authorities list of authoritative books.
With these distinctions in mind, we may now offer several insights into the formation of the New Testament canon. First, many of the New Testament books that we have today were considered functionally canonical very early, perhaps immediately following their composition in the first century. This is not to say that, for example, the Corinthian Church knew that Paul’s letters to them would eventually be considered authoritative scripture by churches everywhere, only that they held those letters (and certain other writing) as authoritative. Second, while a “core” of the New Testament was accepted quickly over a wide geographical area, the functional canon was not really ‘completed’ until the second and third centuries through the influence of outside sources (i.e., the heretics). Third, formal canonization took root in the fourth century (though there were earlier attempts), creating authoritative lists of the books which had been functional and authoritative for generations. Thus, while there are “pronouncements” from bishops and local gatherings of Christians about which books should be included in the New Testament, these lists are not “decrees” setting down something totally new, but rather codification of the books which were already being used by Christians.
 A version of this essay was originally presented to Dr. Margaret Yee at St. Cross College, Oxford University in 2010.  Dairmaid MacCulloch. A History of Christianity. London: Penguin Books, 2010. 78-90.  J. N. D. Kelly. Early Christian Doctrines, Fifth Edition. London: Continuum, 2009. 6.  Ibid., 52-3.  See 1 Clement’s extensive use of the Jewish Scriptures, which functioned as the basis for his practical theology. See also Kelly, 31-2.  Kelly, 53-6. We see this dynamic even at work in the New Testament (Jude 14), where there are relatively few “apocryphal” citations.  John Barton. Holy Writing Sacred Text: The Canon in Early Christianity. Louisville: Westminster John Knox Press, 1997. 32.  Ibid., 2.  J. W. C. Wand. A History of the Early Church to A.D. 500. Fourth ed. London: Routledge, 1965. 12-13.  Barton, 2-4.  Ibid., 5-7.  Barton, 8. See Harnack’s Marcion: The Gospel of an Alien God.  Wand, 44-59. See Bruce Metzger’s New Testament Canon.  Barton, 9.  Ibid., 11.  Ibid., 13.  Typically Matthew, Mark, Luke, John, Romans, Galatians, Philippians, 1 and 2 Corinthians, 1 John, and 1 Peter.  We should also note that while the “main stream” of orthodox Churches, both East and West, affirmed the 27 books now included in the New Testament (though Hebrews and the Apocalypse of John took some additional time to be fully recognized), some churches maintained slightly different lists for centuries. For example, the Armenian Church long used the Epistle to the Laodiceans, and the Ethiopian Church includes the Book of Clement (different from the aforementioned First Clement) and the Didascalia.