The Rule of Faith

The regula fidei — the “rule” or “canon of truth” — is St. Irenaeus’ name for the Church’s open, baptismal summary of the apostolic faith: the storyline that runs from the one God and Father through the incarnate Son to the Spirit and the consummation of all things. For Irenaeus it is the hypothesis of Scripture, the inner plot by which the scattered passages cohere; the Gnostics’ error is to dismember that plot and re-fit the pieces into an alien shape. This proto-creedal rule is the seedbed from which the conciliar creeds would later grow.

Tradition: Pan-Orthodox (Church Father)

The Problem: Scripture Without Its Hypothesis

The Valentinian Gnostics did not reject Scripture; they quoted it copiously. Their method, Irenaeus complains, was to “disregard the order and the connection of the Scriptures, and so far as in them lies, dismember and destroy the truth. By transferring passages, and dressing them up anew, and making one thing out of another, they succeed in deluding many” (Against Heresies 1.8.1; trans. ANF 1). The texts were genuine; the arrangement was the forgery.

Irenaeus reaches for an image that would become one of the most influential in patristic hermeneutics — the mosaic of the king:

Their manner of acting is just as if one, when a beautiful image of a king has been constructed by some skilful artist out of precious jewels, should then take this likeness of the man all to pieces, should rearrange the gems, and so fit them together as to make them into the form of a dog or of a fox, and even that but poorly executed; and should then maintain and declare that this was the beautiful image of the king which the skilful artist constructed… and persuade them that that miserable likeness of the fox was, in fact, the beautiful image of the king. (Against Heresies 1.8.1; trans. ANF 1)

The jewels (tesserae) are the words and episodes of Scripture; the artist’s portrait is the true subject they were composed to depict — Christ and the economy of salvation. The Gnostic takes the same authentic gems and re-sets them according to a different blueprint, producing a fox where there should be a king. The argument is precise: error is rarely a matter of false materials but of a false hypothesis — the governing pattern according to which the materials are assembled (Behr, Irenaeus of Lyons, ch. 4, on hypothesis and oikonomia; Osborn, Irenaeus of Lyons, ch. 9).

This is why simply citing Scripture settles nothing against a Gnostic: both sides hold the same texts. What is needed is the right hypothesis — and that hypothesis is not invented by the exegete but received, in the Church, as the rule of faith.

Two technical terms organize Irenaeus’ thought here. The hypothesis (literally “underlying thing,” plot or argument) is the storyline a text presupposes — for Scripture, the single economy of the one God from creation to consummation in Christ. The oikonomia (“economy,” ordered arrangement) is God’s actual administration of that story in history. The Gnostics err by substituting a false hypothesis — their myth of Pleroma, Aeons, and a botched lower creation — for Scripture’s own, and so misread the oikonomia as the work of an inferior craftsman rather than the one good Creator (Behr, Irenaeus of Lyons, ch. 4; Osborn, Irenaeus of Lyons, ch. 9). The rule of faith, by contrast, is simply Scripture’s true hypothesis made explicit and held in the Church’s hands.

The Rule Stated: Against Heresies 1.10.1

Irenaeus gives the rule itself in a celebrated passage. Its tripartite, Father–Son–Spirit shape, and its movement from creation to incarnation to final judgment and resurrection, make it unmistakably proto-creedal:

The Church, though dispersed throughout the whole world, even to the ends of the earth, has received from the apostles and their disciples this faith: [She believes] in one God, the Father Almighty, Maker of heaven, and earth, and the sea, and all things that are in them; and in one Christ Jesus, the Son of God, who became incarnate for our salvation; and in the Holy Spirit, who proclaimed through the prophets the dispensations of God, and the advents, and the birth from a virgin, and the passion, and the resurrection from the dead, and the ascension into heaven in the flesh of the beloved Christ Jesus, our Lord, and His [future] manifestation from heaven in the glory of the Father to gather all things in one (Eph 1:10), and to raise up anew all flesh of the whole human race… (Against Heresies 1.10.1; trans. ANF 1)

Three features mark this as a rule rather than a private theological essay.

First, it is received, not constructed: the Church “has received from the apostles and their disciples this faith.” The rule is the deposit, handed over.

Second, it is one and universal. Irenaeus immediately presses the point that this faith is identical across the whole inhabited world: the churches “planted in Germany do not believe or hand down anything different, nor do those in Spain, nor those in Gaul, nor those in the East, nor those in Egypt, nor those in Libya”; though human languages differ, “the import of the tradition is one and the same” (Against Heresies 1.10.2; trans. ANF 1). The rule’s catholicity is itself part of its authority — it is not the property of one teacher or school.

Third, it admits depth without admitting addition. Greater eloquence or intelligence may “bring out the meaning of those things which have been spoken in parables” more fully, but no one “make[s] any addition to it” nor “diminish[es] it”; “the faith being ever one and the same” (Against Heresies 1.10.2–3; trans. ANF 1). This is precisely the dynamic the later Orthodox tradition will articulate as Tradition growing by deepening and not by addition (cf. Lossky, in Holy Tradition).

A Second, Christological Rule: Against Heresies 3.4.2

In Book 3 Irenaeus offers the rule again, this time as the faith held by the “barbarian” churches who possess no Scriptures of their own but carry “salvation written in their hearts by the Spirit, without paper or ink.” Their faith is:

believing in one God, the Creator of heaven and earth, and all things therein, by means of Christ Jesus, the Son of God; who, because of His surpassing love towards His creation, condescended to be born of the virgin, He Himself uniting man through Himself to God, and having suffered under Pontius Pilate, and rising again, and having been received up in splendour, shall come in glory, the Saviour of those who are saved, and the Judge of those who are judged. (Against Heresies 3.4.2; trans. ANF 1)

The verbal kinship with the later Old Roman Symbol and the Nicene–Constantinopolitan Creed — “born of the virgin… suffered under Pontius Pilate… rising again… shall come in glory… to judge” — is direct and not accidental. The clause “He Himself uniting man through Himself to God” already carries Irenaeus’ distinctive recapitulative soteriology (see Anakephalaiosis).

It is worth noting that Irenaeus’ rule is not a fixed verbal formula in the way the conciliar creeds are. He states it in varying words (1.10.1, 1.22.1, 3.4.2, and in the Demonstration of the Apostolic Preaching 6) because the rule is the substance of the faith — its hypothesis — rather than an authorized wording. The fixed liturgical and conciliar texts come later; what Irenaeus supplies is the thing the creeds will crystallize (Behr, Irenaeus of Lyons, ch. 4; Behr, On the Apostolic Preaching, PPS 17, Introduction).

The Rule as Scripture’s Own Hypothesis

A modern misreading treats the rule of faith as an external authority over Scripture, imposed from outside. Irenaeus’ own claim is the reverse: the rule is Scripture’s own hypothesis, drawn out and held up so that Scripture may be read as the unified narrative it is. The canon of truth is “received in baptism” (Against Heresies 1.9.4), and by it the believer recognizes the king’s portrait in the jewels rather than the fox.

This yields Irenaeus’ hermeneutical principle: clear passages interpret obscure ones, and the whole is read according to the economy that runs from creation to consummation in Christ. “A sound mind… will set forth all the [Scriptures] in a connected narrative” and will not, on the basis of ambiguous texts and number-speculation, fabricate “another god besides Him who is the Framer, Maker, and Preserver of this universe” (Against Heresies 1.10.3; 2.27.1; trans. ANF 1). The rule does not silence Scripture; it lets Scripture speak with one voice.

How This Grounds the Later Creeds

Irenaeus stands at the headwaters of the creedal tradition. Three lines run from his rule of faith to the symbols of faith confessed in the Liturgy:

Trinitarian structure. The Father–Son–Spirit articulation of 1.10.1 is the architecture the baptismal creeds and then Nicaea–Constantinople will fill out. The creed is, in form, a developed rule of faith.
The economy as narrative. Irenaeus’ insistence that the faith is a story — creation, incarnation, passion, resurrection, ascension, judgment, resurrection of the flesh — is exactly the narrative spine of the Nicene Creed’s second article (“for us and for our salvation came down… was incarnate… was crucified… rose again… shall come again”; cf. Christology and The Nicene Creed).
Catholicity as a criterion. Irenaeus’ argument that the true faith is the one believed everywhere anticipates the Vincentian canon — ubique, semper, ab omnibus — and the Orthodox doctrine of the consensus patrum (see Holy Tradition).

The rule of faith is thus not a quaint second-century antecedent but the living principle the creeds embody: Scripture read in the Church according to its own hypothesis, the king recognized in his portrait. What apostolic succession then guarantees — that this same hypothesis has been handed down unbroken in the churches the apostles founded — is the subject of the companion file, Apostolic Succession.

References

Irenaeus of Lyon. Against Heresies (Adversus Haereses) 1.8.1; 1.9.4; 1.10.1–3; 2.27.1; 3.4.2. Translated by Alexander Roberts and William Rambaut. In Ante-Nicene Fathers, vol. 1. Buffalo: Christian Literature Publishing, 1885.
Irenaeus of Lyon. On the Apostolic Preaching (Demonstration of the Apostolic Preaching) 6. Translated by John Behr. Popular Patristics Series 17. Crestwood, NY: St. Vladimir’s Seminary Press, 1997.
Behr, John. Irenaeus of Lyons: Identifying Christianity. Oxford: Oxford University Press, 2013.
Osborn, Eric. Irenaeus of Lyons. Cambridge: Cambridge University Press, 2001.
Steenberg, M. C. Irenaeus on Creation: The Cosmic Christ and the Saga of Redemption. Leiden: Brill, 2008.
Lossky, Vladimir. “Tradition and Traditions.” In In the Image and Likeness of God. Crestwood, NY: St. Vladimir’s Seminary Press, 1974.