The Living Irenaeus of Lyons: A Blog Series on Against Heresies (Part 1)

Over this past year of 2025, I have been engaged in a personal project involving reading through the two works of Irenaeus of Lyons, Against Heresies and On the Demonstration of Apostolic Preaching, and then condensing and paraphrasing them into more readable English than the formal academic translations that are out there. I started this practice of paraphrasing the early Church Fathers a few years ago, when I taught an “Early Church Theologians” course at the University of North Alabama. In my opinion, most English translations of the early Church Fathers are simply too wordy and cumbersome. They aren’t made for the average English reader who doesn’t have graduate degrees in the Church Fathers. Consequently, that entire world of the early Church Fathers—what they said and what they taught—is completely lost to most Christians. I find that a shame, because there is so much in the writings of the early Church Fathers that can help everyday Christians grow in their faith.

That is why, over the past few years, I’ve started my practice of reading and paraphrasing the writings of various early Church Fathers. In this case, it is the two works of Irenaeus. By the time this blog series is over, my own condensed paraphrase of Against Heresies and The Demonstration of Apostolic Preaching should be available on Amazon. What I want to do in this blog series, though, is to focus on specific things Irenaeus talks about in Against Heresies. It will not be comprehensive—to get a comprehensive understanding of Against Heresies, you’ll have to read the entire thing. But don’t worry. I’ve been able to take 500 pages and condense and paraphrase them down to 260 pages! In any case, all I want to do in this blog series is to share my thoughts on the various things in Against Heresies that stood out to me most. First, though, how about a little background on Irenaeus of Lyons?

A Brief Biography of Irenaeus
It is believed that Irenaeus was born in AD 125 in Smyrna (modern day Izmir, Turkey) on the coast of the Aegean Sea. In his writings, he tells us that as a young man he had listened to Polycarp, the bishop of Smyrna, who had been a disciple of the Apostle John. By sometime around AD 160, Irenaeus moved to Lyons (in modern day France) to become a priest in the Church there. After persecution broke out there, when Pothinus the bishop of Lyons was martyred, Irenaeus succeeded him to become the next bishop of Lyons. He eventually died in Lyons sometime around AD 202.

Irenaeus is most known for two works, Against Heresies and On Apostolic Preaching. The titles pretty much tell what each book is about. In Against Heresies, Irenaeus painstakingly takes the reader through the various teachings and doctrines of the numerous Gnostic teachers and schools. He not only shows how they conflict with Church Tradition, but he also shows them to be ludicrous and illogical in and of themselves. In On Apostolic Teaching, Irenaeus takes the reader through the fundamentals of basic Apostolic Teaching. You can think of the book as truly being a book about the original, fundamentals of the historical Christian faith. 

Against Heresies: The Basics of Gnostic Teaching
Now, trying to understand Irenaeus’ explanation of Gnostic teaching in Against Heresies can be really confusing for the simple fact that Gnostic teaching and terminology is really confusing! Therefore, I want to provide a very brief summary of the basics of Gnostic teaching to help you make your way through the convoluted mess that is Gnostic teaching.

Gnosticism teaches that the material universe was not created by the Supreme God, but by a lesser entity called the Demiurge. That Demiurge, according to them, was the God of the Old Testament. He, though, was not the Father of Jesus Christ. According to the Gnostics, when Jesus spoke of His Father, He was talking about that Supreme God who exists far above the Demiurge and was completely unknown and disconnected from the material creation. The way the Gnostics even get to their teaching about the Demiurge and the creation of the material world, though, is quite a trip! Buckle up.

The Gnostics call the Supreme God Bythus (along with a few other names). He dwells in the spiritual world, far above the material universe. He and his consort Ennoea produced two Aeons, Nous and Aletheia. These four beings formed the First Tetrad.

Nous and Aletheia then produced two more Aeons, Logos and Zoe, and proceeded to form the Pleroma. Logos and Zoe produced two more Aeons, Anthropos and Ecclesia. These first eight Aeons formed the First-Begotten Ogdoad. Logos and Zoe then produced ten more Aeons (all in pairs), and they became known as the Decad. After that, Logos and Zoe then produced twelve more Aeons (again, all in pairs), and they became known as the Duodecad. All those together—the Ogdoad (8), the Decad (10), and the Duodecad (12), form the Tricontad (30)—thirty Aeons in the Pleroma.

Now, Nous was the only one who knew about Bythus. None of the other Aeons could comprehend Bythus or his greatness. It just so happened, though, that one of the Aeons in the Duodecad, Sophia, became inflamed with an uncontrollable passion when she attempted to comprehend the unknown Supreme God, Bythus. Since she was overcome with passion, she was cast out of the Pleroma.

Excluded from the Pleroma, Sophia was so overcome with grief, fear, ignorance, and confusion, that she somehow produced, all by herself, with no help from any masculine Aeon, Enthymesis, as spiritual substance with no shape or form. This Enthymesis was the retarded product of the feminine. But then Bythus, through Nous (with no help from his feminine consort Ennoea), produced another being, Horos, who helped Sophia by taking away Enthymesis from her and also restoring Sophia back to the Pleroma.

Bythus then created, through Nous alone, with no help from his feminine consort Ennoea, two more beings, Christ and the Holy Spirit. Their jobs were to strengthen and maintain the Pleroma, and to teach the other Aeons that Bythus was ultimately incomprehensible. The Aeons were so happy to learn that, they came together to form Jesus (whom they also called Savior, Christ, and Logos) as their way of honoring and glorifying Bythus.

But Enthymesis was still wandering about with no form or shape, outside the Pleroma. So, the Holy Spirit gave her a form, as well as two other names: Sophia (after Enthymesis’ “father” Sophia, the twelfth Aeon in the Duodecad), and Holy Spirit. But the name she is most known by is Achamoth—the “Mother,” ultimately, of the material universe. For she eventually produced the Demiurge, who had an animal nature and was the creator of the material world and all material substances. He, though, was completely ignorant of the existence of his mother, Achamoth. He thought he was the supreme God over all, but he was, in reality, ignorant of, not only his mother, but of the existence of the Pleroma itself.

In the Gnostic worldview, all matter ultimately came from passion—that thing within Sophia that led to fear, ignorance, and confusion. Since human beings are partly matter, they are imprisoned in that material existence. At the same time, though, human beings have received an animal nature as a result of Achamoth’s being freed from her passions. On top of that, human beings also have a spiritual nature that they have received directly from Achamoth.

Therefore, in the Gnostic worldview, the goal for “special” human beings is to eventually free themselves of their material substance and to gain access to the fellowship in the spiritual world. That obviously affects their view of Jesus Christ. Since they see the material world as bad, Gnostics not only deny Jesus’ resurrection, but they also deny the incarnation itself.

There is obviously a lot more to the Gnostic “system.” That is what Irenaeus goes into in considerable depth. Still, if you can understand the basic “backstory” I’ve just shared, you’ll be in better shape to grasp Against Heresies.

Other Major Themes in Against Heresies
I also want to provide a brief overview of some of the major themes in Against Heresies.

The Teachings of the Various Gnostic Schools
In addition to the basic “cosmic worldview” I outlined above, the various Gnostics schools all have their particular views of Jesus, and all of them conflict with the teaching that had been passed down by the Apostles. The most common view is that Christ never really became truly human, with real human flesh. For these Gnostics, human flesh and the material world were bad, gross, ugly, and irredeemable. Christ came to dispense “secret knowledge” to the select few in order to tell them how they can successfully pass through the material world and the influence of the Demiurge, and back up into the pure spirit world. In short, because they deny the goodness of creation, their version of salvation is not the salvation of creation, but rather salvation from creation.

The Unity of Church Teaching, Church Tradition, and Apostolic Succession
Irenaeus takes considerable time emphasizing that whereas these Gnostic teachers were putting forth novel and imaginative claims, the teaching and Tradition of the Church, even the appointment of its bishops and priests, had direct roots to the Apostles themselves. Whereas every Gnostic school was teaching its own unique doctrines, Christians churches throughout the world all shared the same core teachings and doctrines. There was a clear unity of the faith.

Biblical Interpretation
Another interesting thing is how Irenaeus contrasts the ways in which Gnostics interpreted various biblical passages and the way the Church interpreted them. He says time and time again that it all comes down to basic literary competency, reading passages in their contexts, and keeping in mind that the writers often use figures of speech and metaphors that shouldn’t be taken literally.

The Creator God is the Supreme God
Irenaeus is always coming back to this point time and time again. The reason should be obvious. One of the core teachings of Gnostics was that the being who created the world was the Demiurge who came into the being as a result of Achamoth’s fear and ignorance. The Gnostics often called this Demiurge “the fruit of a defect” and insisted that he was far below the Supreme Father who was completely unknowable and had nothing to do with the material creation. For the Gnostics, this Supreme God sent Christ to help people escape from the degrading material world of the Demiurge. For Irenaeus, though, this was the worst kind of blasphemy, for it was calling the Creator, the God of the Old Testament, a lesser being, full of ignorance. And it contradicted what Jesus himself said when He called the Creator God His Father. Irenaeus was insistent: the Creator is the Father, and the Father sent the Son to save and sanctify human beings and to renew His creation.

Jesus is both God and Man
Irenaeus is equally insistent that Jesus Christ was not only the Son, the Word of God, the Logos, but also became a real human being. He took on flesh for the sole purpose of redeeming the flesh. He is how we can come to know the Father. He is through whom we can come into communion with the Father. Through Him, human beings can be saved and sanctified in the flesh. Through Him, creation itself will be renewed.

Irenaeus’ View of Recapitulation
Recapitulation is one of the most significant concepts in Irenaeus. It is rooted in the juxtaposition of Adam and Christ. God’s purpose for humanity was to create “flesh and blood” human beings “in His image” to grow and mature into God’s likeness. But “in Adam,” humanity has suffered corruption and death, and God’s purpose and intention for humanity has been “derailed,” so to speak. Therefore, Christ, the Word, the Son of God, has entered humanity, taken on human flesh, and “summed up” and “recapitulated” humanity within Himself. Basically, in Christ (the second Adam), humanity (the first Adam) now has the opportunity to “get back on track” so that it can get back to growing and maturing into God’s likeness.

Free Will; Mankind was not Created Perfect:
Related to that is Irenaeus’ understanding of mankind, represented in the figure of Adam. Irenaeus emphasizes that God created man with free will because He wanted man to choose to enter into communion with God. Time and time again, Irenaeus emphasizes that God does no coerce or force man to do anything. Similarly, Irenaeus also emphasizes that God did not create mankind (i.e. Adam) “perfect.” Adam represents mankind in its natural, childlike state. Thus, Adam was not created “perfect” and “like God,” only to “fall” from that state of perfection. He was created as a natural being of flesh, but still far from mature and truly “like God.” Achieving that kind of maturity and “perfection” depends on one’s free will. But since Adam (and by extension all humanity) chose to disobey and sin, that God-ordained intention for humanity got derailed. And that, as previously mentioned, is the reason for Christ taking on flesh—to recapitulate humanity within Himself and get it back on track, so that it can grow, mature, become “perfected” in Christ and come to bear the likeness of God.

Typology and Irenaeus’ Understanding of the Torah and Old Testament
Another thing Irenaeus emphasizes is how everything in the Old Testament serves as a type of the future realities revealed in Christ. What this amounts to are many creative, allegorical interpretations of various Old Testament passages in relation to Christ. To be clear, Irenaeus certainly is not engaging in modern, scholarly biblical exegesis that is trying to get at the original meaning of a passage in its original context. He is creatively interpreting and applying various passages to Christ. For him (as with the early Church), the things in the Old Testament serve as types, or foreshadowings, of things to come. Perhaps my own analogy will help. For Irenaeus, things in the Old Testament are like model airplanes, so that when the real airplanes arrive, you will be able to recognize them.

Old Testament Predicted Details of Christ’s Life
Having done my graduate work in the Old Testament, and specifically the Old Testament prophets, I want to take issue with the way Irenaeus presents the Old Testament prophets and messianic prophecy. He claims that the Old Testament prophets predicted things about Christ’s life and ministry. This idea that equates prophecy with “far-off predictions of the future” is something commonly held by most people. I think that is the wrong way to understand Old Testament prophecy. In most prophecies, there was an original context and referent that had obviously come to pass, thus vindicating that prophet and that given prophecy. Basically, the prophecy was fulfilled, that’s why the writings of that prophet were preserved. What the New Testament writers were doing, therefore, was pointing to certain, fulfilled Old Testament prophecies, and then essentially arguing that Christ’s actions were “like that, but bigger.” Therefore, the Old Testament prophecies are just “far-off predictions.” They had an initial referent, but with the coming of Christ, we see those prophecies had an “extra layer of meaning and fulfillment.” Irenaeus, though, doesn’t explain them in that way. I’d like to think that if I could travel back in time, Irenaeus would agree with me that Old Testament prophecies clearly had an original context, and then there is an extra, revealed context in light of Christ. But the fact is, the way he treats Old Testament prophecy in his works, he seems to present them as just “far-off predictions.”

The End Times/Last Days
Much of what Irenaeus says about the “End Times” or “Last Days” might strike to as very similar to your average “End Times preacher” in many Evangelical circles. And Irenaeus does give the impression that he expects the Antichrist to be revealed in his own near future. That is something that requires further reflection. But one thing I found very interesting is Irenaeus’ claim that after the future resurrection, once the New Jerusalem arrives, there will be sort of a “two-tier” division of the redeemed. Those who have been fully perfected will be in glory, in the New Jerusalem. At the same time, there will be those who are redeemed, but who haven’t yet been fully perfected, and who will remain here in this world, during the reign of Christ on earth, who will still be growing and maturing until their physical bodies are able to “bear the glory” of God.

So, there you go! Does Against Heresies sound intriguing? If so, keep coming back to this blog, because I’ll be doing a blog series on it. And if you like the next few posts, go to Amazon and buy my book, The Living Irenaeus of Lyons.