Sometime around 140 and 145 CE, a man named Marcion separated from the church at Rome over severe doctrinal disagreements. Marcion, influenced by another collection of popular ideas historians refer to as Gnosticism, set up his own system of thought that presented an antithesis between the God of the Old Testament and the God of the New Testament. The old God was the creator God as well as a God of justice, who created matter (something considered bad) and angrily inflicted punishment. The new God was the superior God of mercy and goodness who sent Jesus (whose body was only an immaterial imitation of the real thing) to rescue humanity from this material world. Marcion’s antithesis led him to form a list of Scriptures that he was both aware of and which expounded the truth as he saw it: Galatians, 1 and 2 Corinthians, Romans, 1 and 2 Thessalonians, Ephesians, Colossians, Philippians, Philemon, and Luke. Notably, the true significance of this list is what he excluded: the Old Testament, including the OT references in Luke.
Marcion’s influence (as well as many other important figures) forced the 2nd century church to think in greater detail about how “the Scriptures” (still the Old Testament at this point) fit together with Jesus. Yet, Marcion’s limited choice of 10 Pauline epistles and one gospel as authoritative scripture was less radical at the time and points to the incredible amount of debate that went into forming the New Testament. For example, Eusebius’s Ecclesiastical History (a history of the church from Christ to emperor Constantine’s conversion in 313 CE) is reflective of this uncertainty:
Since we are dealing with this subject it is proper to sum up the writings of the New Testament which have been already mentioned. First, then must be put the holy quaternion of the Gospels; following them the Acts of the Apostles. After this must be reckoned the epistles of Paul; next in order the extant former epistle of John, and likewise the epistle of Peter, must be maintained. After them is to be placed, if it really seem proper, the Apocalypse of John, concerning which we shall give the different opinions at the proper time. These then belong among the accepted writings. Among the disputed writings, which are nevertheless recognized by many, are extant the so-called epistle of James and that of Jude, also the second and third of John, whether they belong to the evangelist or to another person of the same name. Among the rejected writings must be reckoned also the Acts of Paul, and the so-called Shepherd, and the Apocalypse of Peter, and in addition to these the extant Epistle of Barnabas, and the so-called Teachings of the Apostles; and besides, as I said, the Apocalypse of John, if it seem proper, which some, as I said, reject, but which others class with the accepted books. And among these some have placed also the Gospel according to the Hebrews, with which those of the Hebrews that have accepted Christ are especially delighted. And all these may be reckoned among the disputed books. But we have nevertheless felt compelled to give a catalogue of these also, distinguishing those works which according to ecclesiastical tradition are true and genuine and commonly accepted, from those others which, although not canonical but disputed, are yet at the same time known to most ecclesiastical writers—we have felt compelled to give this catalogue in order that we might be able to know both these works and those that are cited by the heretics under the name of the apostles, including, for instance, such books as the Gospels of Peter, of Thomas, of Matthias, or of any others besides them, and the Acts of Andrew and John and the other apostles, which no one belonging to the succession of ecclesiastical writers has deemed worthy of mention in his writings. And further, the character of the style is at variance with apostolic usage, and both the thoughts and the purpose of the things that are related in them are so completely out of accord with true orthodoxy that they clearly show themselves to be the fictions of heretics. Wherefore they are not to be placed even among the rejected writings, but are all of them to be cast aside as absurd and impious.
Among Eusebius’s “disputed writings” belong James, Jude, 2 and 3 John, and potentially Revelation (i.e. “the Apocalypse of John”), all of which belong in our current canons and which are as equally regarded as non-canonical books such as the Acts of Paul and the Epistle of Barnabas in Eusebius’s organization. Furthermore, this canonization process was never definitively settled despite the eventual acceptance of a twenty-seven document NT canon as the norm. The Third Synod of Carthage in 397 CE (a local Western synod under the influence of Augustine) produced a canon list that is synonymous with our New Testaments, yet this list never fully caught on in the East. The canon remained fluid in the East for a lot longer, with Revelation being the primary book of contention.
The significance of the canon debates for doing theology can be summed up in three related questions: 1) which books should make up the Bible? 2) how do we use the Bible for theology if we do not even know which books should be regarded as authoritative? and 3) what determines a correct reading of whatever defines Scripture? Rather than answer these questions directly, we might take a lesson from Jesus and from the early church on how to do theology without a New Testament canon.
Jesus and the Hebrew Scriptures
Thankfully, the boundaries of the Old Testament are easier to define, because Jesus is involved. Jesus’s regard for the Old Testament (again, “the Scriptures”) is often a foundational argument for the acceptance of the Old Testament as Christian Scripture, or as a resource which tells us who God is, what God has done, what God may do, what God requires of us, and how we should relate to God. Part of the reason why Jesus’s attitude toward the Scriptures is so foundational to questions about the OT’s significance is that our affirmation of Jesus’s teachings is tied together with Christological questions; if we think Jesus really was with God at the beginning of creation (and is God!), then it is fair to claim he likely knew what he was talking about. Rejecting Jesus’s posture toward the Hebrew Scriptures implicitly means denying the high, authoritative status given to Jesus by even his first followers.
Jesus’s regard for the Scriptures is more of capstone than a defining point of the Old Testament’s authority however, since “scripture’s status derives more intrinsically from its own nature than from Jesus’s endorsement of it, so that the latter is its buttress rather than its foundation.” “The Law and the Prophets” for example claim the authorities of Moses and various prophets, all of which, the Scriptures claim, had a real encounter with God. (The Writings—basically everything else—are kinda weird though) The narratives these texts present ask the reader to consider their authority as the words of God. Jesus simply affirms their question.
On a related note, Jesus’s attribution of Mosaic authorship to the Torah, despite plenty of evidence that Moses did not write it, does not need to be seen as ignorance. Authorship functioned differently in the ancient world, and it may have been acceptable for someone to diminish their own personal significance by writing in a founder’s name, extending the founder’s conversation and authentically reworking it for the present. In light of this, Jesus’s use of the phrase, “the Law of Moses,” is not necessarily misleading. Jesus’s words and actions toward Israel could also be regarded as mirroring God’s actions in the past—accommodating his earthly context by adjusting his message so that it could best be understood. Even more radically, if we are inclined to flirt with the Hebrew Bible more than the presentation of God in Christian orthodoxy, we might say that Jesus shared in the same limitations that characterize the God of the Old Testament.
As far as the outer boundaries of the Old Testament, there is again some disagreement. Various Christian traditions canonize different books from the period between the OT and Jesus (typically referred to as the Apocrypha or Intertestamental Literature). But “nevertheless he [Jesus] does seem to have shared the view of Jews of his day that there were scriptures that had special authority, they seem to have been the same scriptures that these Jews in general accepted, and the books we know as the Hebrew Bible remain as near as we can get to establishing which books they were.” All things considered, the Hebrew Bible is arguably the most solid part of the canon.
The Rule of Faith
Armed with the Old Testament Scriptures and a few assorted biographies of Jesus and letters from Paul, the early church had to figure out how to put it all together in a way that preserved correct beliefs against innovative teachers such as Marcion. This meant ensuring people interpreted their Bibles correctly, which fundamentally required people to view the Scriptures through the correct theological lens. In order to establish a normative theological lens, many leaders of the church, beginning in the 2nd century, employed the Rule of Faith. The Rule was essentially a summary outline of the gospel message, or of God’s purposes, with an emphasis on Jesus’s life, death, resurrection, ascension, and 2nd coming. Like its counterpart with Roman Rule (same latin word: regula), the many forms of the Rule vary depending on the author and context, but they regardless present the same core message. The Rule arose from the same apostolic tradition encoded in the written documents handed down to the Church (considered authoritative at this point but not necessarily canonical), and this tradition included a certain way of reading the Scriptures that had existed long before leaders such as Marcion emerged into the spotlight. Irenaeus provides an early and lengthy example of the Rule of Faith:
The Church, though scattered through the whole world to the ends of the earth, has received from the Apostles and their disciples the faith
In one God, the Father Almighty, who made the heaven and the earth, and the seas, and all that in them;
and in one Christ Jesus, the Son of God, who became flesh for our salvation;
and in the Holy Spirit, who through the prophets preached the dispensations and the advent,
and the birth from the Virgin,
and the passion,
and the resurrection from the dead,
and the bodily assumption into heaven of the beloved Christ Jesus, our Lord,
and his appearing from heaven in the glory of the Father, to comprehend all things under one head,
and to raise up all flesh of all mankind,
that, according to the good pleasure of the Father invisibly, every knee of those that are in heaven and on the earth and under the earth should bow before Christ Jesus, our Lord and God and Saviour and King, and that every tongue should confess to him, and that he may execute righteous judgment over all: sending into eternal fire the spiritual powers of wickedness, and the angels who transgressed and apostatized, and the godless and unrighteous and lawless and blasphemous among men, and granting life and immortality and eternal glory to the righteous and holy, who have both kept the commandments and continues in his love, some from the beginning, some after their conversion.
As illustrated by Irenaeus, the Rule of Faith takes the similar but different pictures of Jesus from the gospels and combines them to produce a picture of Jesus’s life (the gospel message), a story by which we are to read the Scriptures correctly. In other words, the Rule makes concrete what the gospels presuppose, that the Bible needs to be read in light of the significance of the God of the Scriptures who acted in and was Jesus, who was incarnated into flesh, who truly died, and who was resurrected from the dead. Those who deny these basic elements of Jesus’s story will almost necessarily read the Scriptures wrong.
The Rule of Faith provided an authoritative framework for the early Church’s interpretation of the Scriptures. It emerged from those central, undisputed documents that eventually became the NT and stood as an authoritative claim on believers even before the NT itself. It likewise was one of the factors used to decide the outer edges of the NT canon; documents were included or excluded based on whether they agreed with the faith presented by the Rule. Most notably, the gospel message embodied in the Rule of Faith seemingly morphed into the Apostles’ Creed, which orthodoxy considers to be the most fundamental commitment of the faith: Comparative Table of the Anti-Nicene Rules of Faith, As Related To The Apostles’ Creed and the Nicene Creed.
Living With an Open Canon…By Following the Rule of Faith
So what is the Rule of Faith’s significance for us? First, given that the NT canon and creeds partly emerge from this Rule, it should encourage us to respect the early creeds of the Church and their canonical decisions as guides for our interpretation by giving them the benefit of the doubt, even as we ask whether these decisions were truly the best ones that could have been made. Second, the Rule allows us to enter into the conversation of the faith by reminding us that the gospel message (what God did through and in Jesus) is the central commitment—however we may choose to define its specific details—by which we interpret the rest of Scripture. Practically, the Rule presupposes several principles for interpreting the Scriptures:
- Scripture is a “unified narrative” which demands a narrative reading of the gospel as a continuation of the OT narrative
- apostolic tradition is important and should be conformed to
- the Church safeguards the apostolic tradition (or at least is supposed to…I am a Protestant for a reason!)
- with the exception of evangelism, correct biblical interpretation is best done within and for the sake of the Church which affirms the Rule…reading the Bible in other contexts means reading the Bible in a way that does not build faith…the latter type of reading means reading the Bible as any other normal piece of literature
In sum, the outermost boundary markers for the legitimacy of our interpretive activities are whether they conform to the gospel handed down through the Church, respect the OT as useful for teaching about matters of the faith, and whether their focus is centered on the significance of Christ for our present day communities.
Given the contentious nature of canon debates in the 2nd through 4th centuries and their parallels to the modern reevaluation of certain documents such as 2 Peter and the Pastorals, which text criticism has revealed may not belong to the apostolic age, a return to the acceptance of the Rule of Faith as our primary authority might enable us to find some solid footing amidst the uncertainty of canon development. This means affirming with Jesus that God was behind the shaping of the Old Testament and inferring that God was also instrumental in shaping the process that produced the apostolic tradition, a tradition that emerged from God’s original activities through the apostles themselves. We might also say that God was instrumental in shaping the exact edges of the New Testament canon and that we should simply trust in it completely and that annoying seminary students should quit thinking about it thank you very much, but I think this is a fideistic dodge of the actual facts on the ground. It is difficult to see how books like James, Jude, 2 Peter, and 2 and 3 John got in over texts such as the Didache or 1 Clement.
 Craig D. Allert, A High View of Scripture?, p. 89, as well as “Marcionite: Gnostic Sect,” Encyclopedia Britannica. https://www.britannica.com/topic/Marcionites
 Eusebius, Ecclesiastical History, 3.25.1-7, as cited in Allert, Scripture?, p. 132-133.
 Allert, Scripture?, p. 141-145. For greater detail, read chapter 4, “A Closed Second Century Canon?” in Allert for greater detail.
 John Goldingay, Models for Scripture, p. 136-137. Even the “lowest” Christological affirmations in the New Testament recognize Jesus’s authority as someone to be followed and obeyed. I reject the kind of evolutionary historical thinking that sees early Christology as a more accurate Christology that slowly evolved into the high Christology of Jesus’s divinity. Not only do I think Paul wrote Ephesians and Colossians, but earlier does not therefore mean truer. This is a theological judgment disguised as historical examination.
 Goldingay, Models, p. 136.
 Hindy Najman, “Seconding Sinai : The development of Mosaic discourse in Second Temple Judaism,” p. 1-39.
 Goldingay, Models, p. 136.
 Adriani Milli Rodrigues, “The Rule of Faith and Biblical Interpretation in Evangelical Theological Interpretation of Scripture” at Themelios (vol. 43, issue 2). http://themelios.thegospelcoalition.org/article/the-rule-of-faith-and-biblical-interpretation#_ftn6
 Philip Schaff, The Creeds of Christendom: With a History and Critical Notes, Vol. 2, Bibliotheca Symbolica Ecclesiae Universalis (New York: Harper and Brothers, 1877), p. 13-14.
 Allert, Scripture?, p. 55, 125.
 Schaff, Creeds, p. 40-41.
 I made this list in conversation with Rodrigues, “The Rule of Faith and Biblical Interpretation”.