Stewardship of the apostolic deposit of faith, encapsulated and transmitted as the regula fidei, was not an uncontested labor during the patristic era. The primary catalyst fueling this work were adversarial teachings, both from outside and within Christian churches, which sprung up and spread rapidly. By the close of the second century, a class of teachings characterized by their claim of a superior spiritual gnosis, aiming to recast central tenets of the Christian faith through reinterpretation of the Scriptures in concert with reimaginations of the triune God, were in full bloom. During this time, custodians of the regula fidei issued powerful confutations aimed to expose these teachings and their teachers as heretical, protect and promulgate sound doctrine, and guard the church from defections.
Irenaeus of Lyons launched his expansive refutation, Adversus Haereses, with the intention of elucidating the general ideology from which gnostic teachings were purportedly grounded and explaining each distinct teaching, all the while contrasting their sources, methods, conjectures, and claims of superior gnosis with one another and with the apostolic deposit of faith. At the outset of this magnum opus, Irenaeus exposed the central fallacy of this heretical movement: the variegated metaphysical theories propagated by an assortment of teachers were ultimately incompatible, thus lacking coherency with and accountability to one central truth.
In contrast, Irenaeus aggressively countered with two bold claims inherent in the regula fidei. First, unlike the disjointed array of gnostic teachings, the true church possessed and faithfully transmitted consistent, noncontradictory, foundational apostolic teachings, a claim Irenaeus defended throughout his exposition in Adversus Haereses. Second, Irenaeus posited that wherever one might travel, the true church in that location spoke this same faith. The verity of the first assertion presumes the regula fidei as expressed by Irenaeus can be traced back to the apostles and its contents shown to have been maintained without deviation or discord. Proving the second assertion is more challenging. While agreement on the tenets outlined by Irenaeus can be found in the writings of predecessors (Clement of Rome and Justin Martyr) and followers (Hippolytus of Rome and Tertullian of Carthage), the actuality of “one mouth”—a unified voice echoing the regula fidei irrespective of location or teaching prowess—presumes factual and demonstrable practice, not conceptual idealism. Furthermore, this period was awaiting, but absent of, churchwide consensual creed and catechism, a unified framework of ecclesiastical guardianship, and global access to the full canon of Scripture. To effectively substantiate his repudiation of gnostic incompatibility, incoherency, and illegitimacy while advancing stewardship of the regula fidei, the case Irenaeus presented in Adversus Haereses must be shown to validate these claims.
This paper is intended for inclusion in a project tracing the sacred stewardship of essential truths of the Christian faith through major eras of church history. Because its primary arguments rested on the church’s fidelity in preserving and transmitting core beliefs that transcended geographical, historical, and sociocultural boundaries, the testimony offered by Irenaeus in Adversus Haereses identifies a seminal moment in the early stages of this endeavor.