The canonization of Scripture came at a crucial moment in early Christian history. An exhaustive treatment of the historical considerations for canonization will not be achieved in this short essay but, rather, several key factors will be investigated that played decisive roles in the eventual outcome of the New Testament as we know it.
A brief synopsis of those key factors are: 1. There was an overall acceptance of the three Synoptic Gospels, the major Pauline epistles, and Revelation based on traditional, liturgical readings going back to the Apostolic Period; 2. Marcion of Sinope would arrive in the early second century with one of the first collections of “Scripture” – a modified book of Luke and ten epistles — promoting his own brand of theological interpretation; 3. Gnosticism would grow in popularity as its adherents would also collect New Testament “Scripture” and write their own apocryphal texts; 4. Montanists would seek to establish an ecstatic form of new prophecy basing their ideas on an esoteric hermeneutic of the Gospel of John and Revelation.
In response to such influences debates arose to counter heretical claims and assert genuine documents of New Testament Scripture. Irenaeus spoke out against the Gnostics in his Against Heresies. Athanasius circulated his thirty-ninth Festal Letter to counter heretical canon. And, finally, the Councils of Carthage (AD 397), and Rome (AD 382) would recognize the form of the New Testament that we have today.
From the authorship of the New Testament documents to the second century, church liturgy held that portions of Old Testament Scripture and available New Testament texts would be read aloud to the body. This was a time of “embryonic orthodoxy” where Christians revered the Old Testament while already being versed in the Synoptics and many of the Pauline epistles. While not all of the New Testament texts were accepted in a closed collection at this early period, there is evidence that the Apostle Peter regarded the Pauline epistles as Scripture (2 Peter 3:16). Even the Gnostic Basilides, Theophilus of Antioch, and Irenaeus were beginning to refer to the New Testament books as Scripture by the second century.
Marcion of Sinope, the son of a bishop from Pontus, arrived in Rome between AD 135-40 with a collection of a modified Luke and ten Pauline epistles. He quickly inserted himself into the Roman Christian community with a considerable donation and, “the presumption of his orthodoxy” but was expelled a few years later for disputing with the church over his teaching. He taught, among other things, a radical dualism that posited the Creator God and the Christian God as two different beings: one cruel and rigid, the other loving and forgiving. In light of his critical view of the Creator God, Marcion insisted that “Jewish scripture could have no relevance for the church” thereby dismissing the cherished Old Testament books studied at that time.
He organized his own church of Marcionites which quickly grew in popularity to rival the church in Rome. The struggle between Marcionites and Christians grew over the next century as the battle over accepted Scripture would reach a head when, in Easter AD 367, Athanasius of Alexandria would record the first list of accepted Christian Scriptures (exactly matching the books we have today) in his thirty-ninth Festal Letter.
Around the period that Marcion was establishing his heterodox teachings, the Gnostics were also compiling their own version of Scripture. While they shared some of the basic beliefs of Marcionites, the Gnostic mythologies ran much deeper asserting a spiritual struggle between higher (pleroma) and lower (demiurge) realms where humans are essentially spiritual entities awaiting enlightenment. Particularly appealing to their esoteric hermeneutic, the books of Genesis, the Gospel of John, and the epistles of Paul were of great interest. They also began to write their own apocryphal texts, as the Nag Hammadi Library confirms, such as the Gospel According to Philip, Thomas, and the Gospel of Truth.
Irenaeus of Lyons attempted to deal with the Gnostics by writing his Against Heresies where he said, “… [the Gnostics] lift up their own opinions against God, inflated by a vain presumption and unstable glory…” Irenaeus appealed to the Rule of Truth (or Faith) as a means to remind Christians of the tradition of which they were already familiar; which simply furthers the case that, at base, the New Testament canon grew out of the recognition of time-honored texts already instituted by church liturgy from the Apostolic Period. As a matter of fact, much of the polemics written by heresiologists in response to heretical teachings were an appeal to return to what Christians already knew to be established.
Lee Martin McDonald writes, “Irenaeus and the other church fathers argued against the Gnostic Christians not by limiting a collection of sacred scriptures (a biblical canon) or by arguments for limiting the number of Christian writings, but they answered rather with the truth of the ‘rule of faith’ (the regula fidei).” This regula fidei had been passed down through the church by apostolic succession and was the key to discerning between the earliest teachings and traditions and the more recent heretical ones. So, while the Christian community had many works to choose from in terms of religious doctrine, the ones determined by the regula fidei won the day for the greater community’s struggle for canon.
The Montanists emerged in popularity from Phrygia in Roman Asia Minor around AD 172. Led by Montanus, who held no church rank, the movement was marked by its adherents’ ecstatic prophetical utterances that, oftentimes, bordered on gibberish and appealed to the Paraclete (Holy Spirit) as its ultimate authority. The New Prophecy, as it was otherwise referred to, focused on the imminent return of Christ and held to a rigid form of ascetism that frowned upon marriage, promoted extended fasting, and limited diet. Montanism arose particularly at a time, “… when consolidation of catholic order and conformity to apostolic tradition preoccupied the bishops.”
Sensitivities to other contemporary heresies were reaching a crescendo as Montanists became the last of a three-tiered heretical attack against orthodoxy in the second century. In spite of this perception, the movement could not be labeled a heresy per se even though their peculiar performances while “prophesying” became a threat to both episcopal and scriptural authority; especially in light of their focus on the Gospel of John and Revelation as a means to explain their source of authority (i.e., the Paraclete).
In response to these heresies that persisted through the second, third, and fourth centuries, councils were formed to determine once and for all the accepted canon of New Testament Scripture. This was at a pivotal moment in the history of the church where, as R.M. Grant puts it, “The question of the formation of a canon was closely related to the question of defining Christianity itself.”
The first council of note is the Council of Rome or the Damasine Synod in AD 382, of which Jerome was present, that established the same canonical books for the New Testament that Athanasius argued for in his Festal Letter. The second is the third Council of Carthage in AD 397, of which Augustine was present, that established the canon of the entire Bible including the same twenty-seven books from the Damasine List. This time the Carthaginian Canon explicitly stated that nothing else be read in the churches other than the books established in the canon.
Both councils applied a system that accepted books into the canon that, overall, conveyed the same message and rejected those that differed by scrutinizing and comparing each book. As was mentioned previously, some of the books were already accepted (and others chosen) that remained within the scope of early church tradition and contemporary consensus. In light of the nearness of both councils (only fifteen years apart) and, “backed by the scholarship of Jerome and Augustine respectively, there could no longer be much question of [Scriptural] disagreement in the West.”
 R.M. Grant, “The New Testament Canon” in The Cambridge History of the Bible Vol. I: From the Beginnings to Jerome, edited by P.R. Ackroyd and C.F. Evans, 286. New York: Cambridge University Press, 1970.
 Ibid, 293-294.
 Harry Y. Gamble, “Marcion and the ‘canon’” in The Complete Cambridge History of Christianity Vol. I: Origins to Constantine, edited by Margaret M. Mitchell, Frances M. Young and K. Scott Bowie, 196. New York: Cambridge University Press, 2006.
 Ibid, 200.
 Ibid, 213.
 G.L. Borchert, “Gnosticism” in Evangelical Dictionary of Theology, 2nd ed., edited by Walter A. Elwell, p. 486-487. Grand Rapids: Baker Academic, 2001.
 Ibid, p. 486.
 Irenaeus, Against Heresies Vol. 2 (Whitefish: Kessinger Publishing LLC, 2010), 85.
 Irenaeus, Against the Heresies Vol. 1, 55 (Mahwah: The Newman Press, 1992), 48-49.
 Lee Martin McDonald, The Origin of the Bible: A Guide for the Perplexed (New York: T&T Clark International, 2011), 167.
 D.F. Wright, “Montanism” in Evangelical Dictionary of Theology, 2nd ed., edited by Walter A. Elwell, 790. Grand Rapids: Baker Academic, 2001.
 R.M. Grant, “The New Testament Canon” in The Cambridge History of the Bible Vol. I: From the Beginnings to Jerome, edited by P.R. Ackroyd and C.F. Evans, 299. New York: Cambridge University Press, 1970.
 Ibid, 284-285.
 Alexander Souter, The Text and Canon of the New Testament (New York: Charles Scribner and Sons, 1917), 197.