Irenaeus and Two Books Theology

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Note: In this and his previous series, theologian Mark Mann argues that Christians should think of Scripture and Creation as two “books” to be read together for understanding the fullness of God’s self-revelation; that science is a God-given tool for discerning the handiwork of God in Creation and is fully compatible with God’s Word revealed in Scripture; and, therefore, that Christians have nothing to fear from science. Here, Mann explores the history of the Two Books Theology in the writings of Christian theologians from the 2nd to 18th centuries, from Justin Martyr to John Wesley. Please see the series introduction for a full explanation of his thesis, concerns, and methods.

Irenaeus of Lyons and the Two Books

We know very little of the lives of most Christian leaders of the 2nd century with any degree of certainty. Much is claimed about them in later traditions, but it can be difficult to discern what is actually true and what is merely legendary. Such is the case with Irenaeus of Lyon. Scholars believe that he was born in Smyrna in Asia Minor (now Turkey) between 130 and 150 CE. His family was apparently Christian, and from an early age he apparently sought preparation for Church ministry. Some traditions cite him as a student of Polycarp of Smyrna (who is supposed to have been a disciple of the apostle John), while others claim him a student of Justin Martyr (about whom I wrote in my previous blog) in Rome in the years leading to Justin’s execution by Roman authorities.

Irenaeus was apparently sent by the Roman church to Lugdunum in Gaul (now Lyons, France) to help minister to the growing number of Christians in that town. Records show that most Christians there were immigrants from Greek-speaking regions of the Roman Empire, and Irenaeus was a Greek speaker. Irenaeus became bishop of Lugdunum around 177 CE, following the martyrdom of his predecessor, and remained in that post until his death in or around the year 202. Although the cause of his death is unknown, there is some evidence that he, too, suffered a martyr’s death.

Irenaeus was a prolific writer but, as was the case with Justin, most of his writings have not survived. Fortunately, the writing considered most important by subsequent Church leaders and theologians has survived—his Against Heresies.1 In this lengthy treatise, Irenaeus writes polemically against a variety of different teachings that he deemed to be false (all of which the orthodox Church would also come to reject). Most of the treatise, though, takes aim at Gnostic teachings that had begun to gain a foothold in the Church, and Irenaeus' chief Gnostic target is Valentinianism.

I have treated the Gnostic heresy at length in another blog, so will not give it a full treatment here, but the Valentinian variety of Gnosticism is worth mentioning briefly. Valentinus was a Christian teacher who (like Marcion, whom I discussed in my discussion of Justin) rejected any identification between the God and Father of Jesus Christ and the creation of the material world. Like most Gnostics, Valentinus had a negative view of materiality and believed that Christ had come to free our spirits from their bondage in the physical world. Valentinus also claimed to possess secret knowledge (gnosis) for achieving such freedom that had been passed on to him but had originated with Jesus himself. During the middle of the 2nd century, Valentinus apparently had a school and disciples in Rome. There is also some indication that he might have been a candidate to become bishop of Rome around 150 A.D., but when his candidacy failed, he apparently left the Church (like Marcion) and founded his own movement. Some scholars suggest that the incursion of Valentinian teachings into churches in Gaul was the precipitating factor for Irenaeus' writing of Against Heresies.

Irenaeus' response to Gnosticism is significant for our discussion of the development of a "Two Books" theology in two respects. First, Irenaeus appears to have been a pivotal figure in the formation of the Christian Bible—the book of Scripture. As noted in my previous blog, while 2nd- century Christians were generally in agreement about the authority of the Hebrew Scriptures (notable excepts, like Marcion, notwithstanding), there was no consensus about which of the writings attributed to the apostles should have the same level of authority. Moreover, Gnostic Christians like Valentinus claimed to possess writings passed down from the apostles, as well.2 In response to the confusion resulting from the circulation of so many different and often conflicting writings attributed to the apostles, Irenaeus published a list of sixty-six books he believed to be authoritative in matters of Christian faith and practice. This list perfectly coincides with the books of our current Old and New Testament, and it is the first such list including all sixty-six that is known to have been published. It would still be a couple generations before Irenaeus' canon of Scripture would be formally accepted throughout the Christian church, but that it would become so is in large part because of the enduring influence of Irenaeus, himself.

Irenaeus is also a pivotal figure in the development of the Christian understanding of Creation. Against the Gnostics, who generally had a poor view of the material world because they considered it the realm of ignorance and/or evil, Irenaeus reveled in Creation’s goodness and beauty. While the Gnostics believed that Creation is the handiwork of some petty or ignorant lesser deity (often called "the demiurge") and that Jesus had come to reveal the true Father and rescue us from our bondage to ignorance and evil, Irenaeus affirmed that the entire universe had been created by none other than the Father of Jesus Christ. While Gnostics believed that Jesus only "appeared" to take on physical flesh, Irenaeus boldly declared that God, in Christ, became flesh and walked among us as a real human being. Indeed, claimed Irenaeus, in the human, material, fleshly Jesus, the very divinity of God is made perfectly visible to us.

Let us reflect on this point for a moment. The Gnostic impulse is to see physicality as an embarrassment. Ultimately, human beings are spiritual beings intended for a purely spiritual existence, but somehow we have become trapped in prisons of flesh. But according to Irenaeus, it is exactly in finite, mortal flesh that God has chosen to be revealed. The material world is not somehow opposed to God or a realm from which God is absent. Quite the contrary, it is God's wondrous Creation, and every little piece of it bears witness to the wonder and majesty of the One true God who is its creator, redeemer, and sustainer.

Irenaeus would drive this point home again and again in his writing. Take, for instance, his view of human beings. He took quite literally that human beings had, by divine purpose, been created from the very dust of the earth intended for life on this earth. Again, he seemed to revel in human physicality. He took great joy, it seems, in speaking of humanity as creatures of dirt and dust, at pointing out our connection to the ground and earth. For Irenaeus, our fleshiness is nothing to be embarrassed about or to regret. It is how God intended from the beginning for things to be. This is why God chose from before Creation to become incarnate. The universe is, for Irenaeus, a kind of canvas upon which God has chosen to draw the very beauty of God's own glory, and God will not complete the masterpiece until Christ's final coming in victory and glory.

It is at this point that Western Christians find Irenaeus most difficult to comprehend. We tend to look at the world through Augustinian eyes. Augustine of Hippo (whom we will look at more closely in a later blog) understood Creation to be complete and perfect with the creation of humanity. For Augustine, the sin of Adam and Eve was the moral failure of two spiritually mature adults, their sin an act of utter rebellion, and the consequences devastating for the whole world and for all subsequent people. But Irenaeus (who lived two centuries before Augustine) instead believed that God created the universe incomplete and imperfect. For Irenaeus, Adam and Eve were like children, created by God to learn and to grow. And learning and growing includes making mistakes. And their sin was a real mistake, but not the devastating mistake that it was for Augustine and most subsequent Western Christians. For their mistake was anticipated by God, and was never intended by God to be the last word on humanity. Rather, the incarnation—God in the flesh—was the Word from the beginning, and it would be the final Word in creation as well.


As with Justin Martyr, Irenaeus does not explicitly affirm a Two Book theology. But, it is not difficult to see the foundations for one in this work. For one thing, he is a pivotal figure in the formation of the Book of Scripture—one of the first (and certainly the most influential) early Christian leaders to affirm the formal authority of the Christian Bible as we know it today. More to the point of this essay series (since most readers will likely already affirm the authority of the Book of Scripture), possibly no theologian in the history of the Church has more explicitly affirmed the extent to which Creation makes visible the wonder, goodness, and beauty of the Creator. It is difficult to imagine him mistrusting the study of God's Creation (science) in the way that so many Christians seem to mistrust it today. Indeed, it is far easier to imagine him as an advocate of all endeavors that help us better understand the wondrous universe that our God has created, for such studies can only help us see more vividly the beautiful artistry of our God, and worship the One through whom God will complete this great masterpiece.


1. The actual title is “On the Detection and Overthrow of Knowledge Falsely So Called,” but is often referred to as “Against Heresies” because the oldest extant copy is found in the Latin text titled “Adversus Haeresus.”
2. These were generally unknown to scholars until the discovery of a Gnostic library in Nag Hammadi in 1945. One gnostic writing, the so-called "Gospel of Judas" is mentioned by Irenaeus, but was otherwise unknown to scholars until it was rediscovered in 1983.




Mann, Mark H.. "Irenaeus and Two Books Theology" N.p., 27 Nov. 2012. Web. 16 January 2018.


Mann, M. (2012, November 27). Irenaeus and Two Books Theology
Retrieved January 16, 2018, from /blogs/archive/irenaeus-and-two-books-theology

About the Author

Mark H. Mann

Mark H. Mann is the director of the Wesleyan Center, Point Loma Press, and Honors Program at Point Loma Nazarene University. Mark received his bachelor's degree from Eastern Nazarene College and went on to earn both an M.Div. and a Ph.D. in Religious and Theological Studies (2004) from Boston University. Mann previously served at Colgate University where he was both chaplain and professor. Mann has previous experience in editing, student development and staff ministry at the local church level.

More posts by Mark H. Mann