Rule of Faith

What safeguards were in place to ensure that the truth of the Christian faith was preserved and passed on to subsequent generations, when the last of Christ’s apostles passed from the scene at the close of the first century? Was the apostolic deposit sufficient to ensure that the early church continued to be the church of Christ? Post-Enlightenment denominations such as the Christadelphians, which claim to be “the modern revival of the apostolic faith,” assert that the church apostasized widely from the beginning of the post-apostolic era. Often, diverse doctrines with which Christadelphians disagree are lumped together and stamped with the defamatory label of “the Roman apostasy.” Even in those very early days, it is claimed, the bishops usurped an authority and infallibility in matters of doctrine and the church councils and hierarchy suppressed any dissent in matters such as the Trinity and the immortality of the soul. Christadelphians claim that they have shaken off the influences of “Christendom” and returned afresh to the Bible. They alone, free of 1800 years of erroneous baggage, have identified the long neglected truths of Scripture. They alone represent the revival of the first century Christian faith.

There are several problems with this position, fundamentally that it denies Christ promised to be with his church to the end of the age (Matt 28:19–20; John 14:26; 16:7–13). Certainly, false teachers and apostasies were predicted and there are clear hints of the nature of these even in the later New Testament writings (Acts 20:29–30; 1 Tim 6:20; 2 Tim 4:3–4; 2 Pet 2:1; 1 John 2:22; 4:1–3; 2 John :7). But Christ taught that his kingdom (reign) would experience steady growth and development, not come to a complete halt for nearly two millennia before being reinvented (Matt 13:24–33). The tares would grow along with the wheat until the harvest time. Furthermore, the apostles’ influence cannot be considered to have ceased when they died, and foundational doctrinal concepts concerning the nature of the Godhead and of Jesus Christ, in continuity with New Testament teaching, can be demonstrated in the earliest extant writings of the church. These doctrines were believed, unpacked, discussed, explained and finally expressed in creeds well before the Roman medieval church usurped doctrinal “authority.”

The apostolic influence continued beyond the first century and was absolutely central to the orthodox churches’ beliefs and practice. It took the form of an acknowledged “rule of faith,” and was the major criterion influencing the final recognition of the scriptural canon. There is strong evidence the components of what became the New Testament were completed and in circulation by about the end of the first century, individually and in small collections. The period of oral transmission of the Gospel tradition was quite short and occurred within the lifetime of the apostles. We can have confidence that what the apostles committed to writing in the first century was an accurate reflection of the life and teachings of Jesus of Nazareth, as well as their own ongoing tutelage under the inspiration of the Holy Spirit. Citations and allusions appear throughout early Christian writings of different genres and diverse locations. They were revered as Scripture; they were the apostolic deposit.

In the Apostle Paul’s last days, when the number of apostles was dwindling, he wrote to Titus and to Timothy as the next generation of church leaders. Titus was to appoint elders, who would “teach what accords with sound doctrine” (Titus 1:5, 9; 2:1, 15). Titus had “all authority” in teaching the sound doctrine and way of life he had learned from Paul. Likewise, Timothy was to oppose heresy and know what constituted right doctrine and behaviour (1 Tim 1:3–4; 4:6). Paul gave him a summary of the gospel which is, essentially, an early statement of the rule of faith (1 Tim 3:15–16). He was to “keep a close watch on yourself and on the teaching. Persist in this, for by so doing you will save both yourself and your hearers”(1 Tim 4: 16). In Paul’s final letter before he was martyred, he exhorted Timothy to “be strengthened by the grace that is in Christ Jesus, and what you have heard from me in the presence of many witnesses entrust to faithful men who will be able to teach others also” (2 Tim 2:1–2). “Do your best to present yourself to God as one approved, a worker who has no need to be ashamed, rightly handling the word of truth” (1 Tim 2:15). False teachers would come, bringing false doctrine and associated unwholesome practices; Timothy must not give way to them, but “continue in what you have learned and have firmly believed, knowing from whom you learned it,” adhering to the truth of inspired Scripture (2 Tim 3:14–16) which included Paul’s own writings. These “pastoral epistles” are essentially exhortations, with specific examples, to carry on teaching and living by the apostolic rule of faith. Both Timothy and Titus provide examples of a biblical apostolic succession.

This apostolic charge to the second and later generations of Christian leaders, known as “overseers” (episkopoi or bishops) was taken very seriously. It is unthinkable that a major diversion from apostolic teaching was on the agenda of the church in this period, nor that it would be permitted either deliberately or inadvertently. In the early days, the overseer or bishop carried the huge responsibility of maintaining conformity with the rule of faith. Ignatius of Antioch, on his way to martyrdom, was worried about the rising influences of heresy, and concerned with the unity of the church against it. He wrote at least seven letters in which he encouraged the Christian communities to “be established in the doctrines of the Lord and the apostles, that so all things, whatsoever you do, may prosper both in the flesh and spirit; in faith and love, in the Son and in the Father and in the Spirit…Be subject to the bishop (episkopos) and to one another, as Jesus Christ to the Father, according to the flesh, and the apostles to Christ…” (Magnesians 8) Ignatius believed that the bishops should be respected as representing Christ and the presbyters (elders) as apostles. In the New Testament there is no functional difference between a bishop and an elder, but as the faith spread, and whilst most churches were house churches, with multiple churches in a regional “church,” a single overseer from amongst the presbyteroi gained responsibility overall. There were no more living apostles, but the bishop ultimately had the responsibility of preserving and teaching the apostolic rule of faith in his community, as had Timothy and Titus before him. It was the content of the bishop’s teaching and example, continuing that of the apostles, rather than any personal connection to them, that was most important. With this authority came great responsibility, but conversely, the bishop who fulfilled this responsibility was regarded as possessing authority, so long as his life and doctrine were in keeping with the rule.

The Greek word kanon meant a measure or rule by which truth could be judged. Initially this was applied not specifically to a body of literature, but to the known and accepted body of apostolic doctrine. This doctrine was enshrined and detailed in the circulating Scriptures and was fully congruent with the accepted corpus of Old Testament Scripture. The apostolic writings were “Scripture” because they were apostolic and conformed to this canon or measurement of truth. Such was the authority of the apostles that, when they died, their verbal and written teachings continued to be the canon or rule of faith, the apostolic deposit. Other writings, even though they might be edifying and truthful, did not carry the same authority.

When the church was challenged by apostasies from the second century onward, it was to the rule of faith that it turned. When Marcion produced his highly redacted set of “scriptures” consisting only of selected Pauline letters and a “mutilated” version of Luke’s Gospel, the church had to defend a larger “canon.” When the Montanists claimed to have additional revelations from the Spirit, the church had to defend a closed and complete “canon.” Thus it became necessary to agree on the books and letters which would be accepted as authoritative. The definitive writings had been circulating since apostolic times, clearly conformed to the rule of faith and were already accepted as Scripture. Even though the New Testament as we know it had not been precisely defined in the second and third centuries, an argument cannot be made for an abandonment of the apostolic writings nor any marked deviation from them.

Even before the New Testament was formally defined, apostolicity, or conformity to the rule of faith was essential for the church. Individual churches were “Christian” if they subscribed to the rule, if they could demonstrate continuity with the apostolic traditions. Some churches could claim to have been founded by the original apostles or their immediate disciples. Irenaeus in the late 2nd century recalled his mentoring by by Polycarp of Smyrna who had been a direct disciple of John. Although beset by heresies such as Gnosticism, Docetism, Marcionism, Ebionism, Modalism and Arianism, the church as a whole did not depart from its rule of faith. It was the measure against which such apostasies and heresies were compared and found wanting. In times of persecution, Christians were willing to die for the faith it encapsulated, and to be killed rather than surrender the Scriptures for destruction. The church was fanatical about maintaining apostolic doctrine and practice.

After the formal agreement on and definition of the “canon” of Scripture, ecumenical creeds became the dominant summary of the “faith once delivered to the saints.” The rule was nevertheless distinct from early creeds, which were its expression within a particular context, typically to refute certain contemporary heresies. Then, as now, it was not enough to claim to be “Christian;” one had to demonstrate concordance with the rule of faith in doctrine and manner of life. The early Christian communities were widespread and culturally diverse and this provided common ground. The actual term used for the rule varied, but it can be shown that “the faith,” “rule of faith, “canon of truth,” “the truth” and similar expressions all referred to summaries of the apostolic faith preached and taught by the churches.

There are many references to such a rule or canon from the earliest church writings. Clement of Rome (late first or very early second century) refers to “the well-esteemed and noble rule (kanon) of our tradition” (1 Clem 7.2). Justin Martyr c165 AD answered the question, “What is your dogma?” with a brief statement about the one God as the Creator and the Lord Jesus Christ, the Child of God, proclaimed by the prophets as the herald of salvation (Acts of Justin 2). In the late second century, Irenaus of Lyons wrote his massive anti-Gnostic treatise Against Heresies, and a guide for catechumens titled Demonstration of the Apostolic Preaching. His favourite descriptor was “the canon of truth” by which he meant the truth itself as the rule or measure, rather than a standard for determining “truth.” He asserted the inspiration and canonicity of the four Gospels and gave summaries of Christian faith in his various works, such as

Believing in one God, Creator of heaven and earth and all things in them, through Christ Jesus the Son of God. He because of his preeminent love for his creation submitted to birth from a virgin, uniting through himself man to God, and having suffered under Pontius Pilate, and rising again, and being received in splendour, coming again in glory, the Saviour of those who are saved and Judge of those who are judged, sending into eternal fire those who change the truth” (Against Heresies 3.4.2).

Terullian of Carthage, writing in Latin around the turn of the 2nd to 3rd centuries, also repeatedly mentions the rule of faith.

The rule of faith is entirely one, alone immoveable and unchangeable. The rule is that of believing in the one almighty God, the Founder of the universe, and in his Son Jesus Christ, born from the virgin Mary, crucified under Pontius Pilate, raised from the dead on the third day, received into the heavens, sitting now at the right hand of the Father, going to come to judge the living and the dead through the resurrection of the flesh… This law of faith is constant” (Veiling of Virgins 1.3–4).

Numerous other examples from ante-Nicene Greek and Latin writers are extant, all very similar. They are used in the context of distinguishing true faith from heresies and expounding the true and normative (exemplary) Christian way of life and typically follow a pattern similar to that of the Apostles’ Creed; God the Creator, the Son and his incarnation, life, death, resurrection and ascension, the Holy Spirit, the church and believers. These recurring topics reflect the essentials of the faith in the second and third centuries and the same framework extends to later creeds. Adaptations and extensions of this basic doctrinal summary represent different contexts. In Acts 2 and 4, the Apostles Peter and John presented a statement of faith that primarily focused on the identity of Jesus in the context of fulfilled prophecy and salvation through resurrection. They did not need to emphasise the oneness of God the Creator because their audience was Jewish. The Holy Spirit’s activity was related to the prophecy of Joel. The second century confessions, expressions of the rule and the Apostles’ Creed necessarily emphasised the things which pagans and dualistic heretics disputed; God as Creator, the incarnation and true humanity of Jesus and the resurrection of the flesh.

Baptismal confessions likewise were in conformity with the rule of faith but were not themselves the “rule.” The rule represented the churches’ understanding of apostolic and scriptural truth; the confession was the individual’s personal commitment to that rule. By the third century, a three year period of instruction (catechesis) and spiritual mentoring was the prelude to baptism and full membership of the body of Christ. Interestingly, the majority of this time was spent in reforming the catechumen’s way of life from idolatry and demonstrating their growth in holiness. Only once their manner of life was deemed consistent with the rule did they receive formal doctrinal instruction in preparation for baptism. With the threat of persecution and the radical change of life required to live as Christ in pagan society, conversion in the early church was no mere assent to head knowledge.

What stands out in all these early expressions of the rule, the beliefs most central to the Christian faith, is how Christ-centred they were, both doctrinally (confession of Christ as Lord) and ethically (living in Christ). This is much more in keeping with Scriptural descriptions of the heart of gospel preaching (Acts 8:35; 10:36–43; 13:32–38; Rom 1:1–6, 16; 1 Cor 15:3–4; 2 Cor 4:4–5; 2 Tim 1:8–10; Heb 6:1–2) than intellectual acknowledgement of a didactic list of “things concerning the kingdom of God and the name of Jesus Christ”(Acts 8:12; see Dianoigo articles below). Early Christians knew they already lived under the reign (kingdom) of Christ and that their citizenship was heavenly, not worldly (Matt 12:28; Luke 17:21; John 6:47; 15:19; Eph 1:3; 2:5–7; Phil 3:20; Heb 12:23; 13:14; 1 John 5:13). Christ is Lord, Caesar was not and death in this life was merely a gateway to the resurrection life. For this unshakable belief they were prepared to die.

The rule was upheld even as baptismal confessions and creeds developed in parallel with the mature preaching of the church. Each of these served a different purpose but conformed in content with the rule and with Scripture, developed to serve different contexts. The rule was the basis of preaching, teaching and refutation of heresy, distinct in function from scripture but never set over against it as a separate authority. The rule allowed for some exegetical freedom and variation in details of practice within appropriate, simple and clearly defined boundaries that had their basis in Scripture. Difficult passages were to be interpreted in the light of simpler ones, and the overall testimony of Scripture as outlined in the rule of faith. An interpretation that pushed Christ away from his central position in salvation, or that attributed Creation to another god, for example, would fail to measure up to the rule and therefore be rejected.

So where did things go wrong? In time, several large church communities, each with a historical apostolic connection, rose to prominence; Antioch in Syria, Alexandria in Egypt, Ephesus and of course Rome. They became centres of scholarship and influence. By the mid to late third century Cyprian, bishop of Carthage, taught that a bishop derived his authority from Christ’s commission to Peter (Matt 16:18–19), but in a general sense that did not imply primacy of the Roman bishop. The bishop, said Cyprian, was the focus of unity for the church and had discretion in a number of matters, provided he maintained the unity of the apostolic faith. Bishops were ideally autonomous within their jurisdictions, but major issues should be handled by councils of bishops.

The major turning point came with the reign of Constantine, when the church became a legal entity with imperial support. Suddenly, bishops became powerful; secular authority and ecclesiastical authority were combined and confused. By the mid 5th century, Rome had fallen and the imperial capital was thoroughly established at Constantinople. In the east, emperors exerted great influence on bishops. In the west, the bishop of Rome gained ascendancy in secular matters with the disappearance of effective imperial power. The Roman bishops claimed authority over the church as a whole, along with the old imperial title Pontifex Maximus. Membership of the Roman version of the catholic (universal) church came to mean communion with the bishop of Rome who claimed direct succession and authority from Peter and thus from Christ. Ultimately, the church came to view itself as the master of Scripture, rather than its humble disciple. Oral traditions and established practices of the church, as well as subsequent “infallible” revelations were of equal or perhaps even greater authority than the written Scriptures, which were held to contain only part of the church’s deposit of doctrine.

This was a far cry from the embedding of the original rule of faith in apostolic doctrine. What is important to understand is that the great orthodox doctrines of the church which had their roots firmly in the apostolic rule of faith and the New Testament, were established before the papacy gained sway over medieval theology and church practice. The doctrines of the Trinity and the two natures of Christ, in particular, had been part of that rule since the early second century, in continuity with the apostolic and immediately post-apostolic age. Certainly those doctrines were explored, discussed, argued over, elaborated and refined in their expression, as the church encountered heretical teachings, but this did not represent a deviation from the rule of faith. The sacramentalism and distinctively Roman Catholic doctrines were a later development, as the church left its humble, unworldly roots and embraced a secular power the apostles could not have envisioned.


For further reading on this topic see
Gerald Bray, The Church: A Theological and Historical Account (Grand Rapids: Baker Academic, 2016).
Everett Ferguson, The Rule of Faith: A Guide (Eugene OR: Cascade, 2015).
Donald K McKim, Theological Turning Points: Major issues in Christian Thought (Louisville: Westminister John Knox Press, 1988) Chapter 6 “Authority Controversy.”
Paul D Wegner, The Journey from Texts to Translations: The Origin and Development of the Bible (Grand Raids: Baker Academic, 1999) Chapter 9 “Canonization of the New Testament.”
Thomas Farrar, Dianoigo and


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