Against Heresies Summarized | Early Christian Writings

In AD 178, when Irenæus was appointed by the Christians in Lyons to be their church’s bishop (or overseer), he had at least three enormous tasks in front of him. 

  1. Many families in his congregation were grieving the losses of nearly fifty martyrs from the previous year. 
  2. The Gospel needed to be spread into the region surrounding Lyons, where people were polytheists or atheists, or the Christians needed their local churches to be organized.
  3. There were discussions and disagreements between Eastern and Western Christians regarding how to respond to heretical groups claiming to be Christians, who were seeking to gain converts away from the universal church.

Among the heretical groups who were falsely identifying as Christians were those later referred to as Gnostics. The word gnostic derives from the Greek word gnosis, which translates in the English to knowledge. Although the Gnostics were not a single group, they did share some general theological tendencies. Irenæus believed the Gnostics presented a serious threat to the correct presentation of the Gospel and to the unity of the universal church. He therefore collected as many Gnostic writings as he could find and wrote a detailed exposé of Gnostic beliefs and behavior. The full title of Irenæus’s exposé is A Refutation and Subversion of Knowledge Falsely So Called, but in time Christian scholars have shortened the title to Against Heresies. It was written sometime between AD 182-186 and is considered to be the best description of Gnosticism from the early church era.

Against Heresies is organized into five distinct books. The first book is an exposition of the beliefs and behavior of various Gnostic groups. Of the Gnostics, Irenæus wrote, “these men falsify the teachings of God and prove themselves to be evil interpreters of the good word of revelation. They also overthrow the faith of many by drawing them away under the pretense of superior knowledge.” Modern literary scholars would classify ancient Gnostic literature as fantasies. Gnostic teachers created very elaborate explanations of divine beings known as Aeons (EE-onz) and how the Aeons brought into being all non-physical and physical reality in the universe. Gnostics taught that the Aeons wished to know their origin from their original Aeon (variously named Proarche [PRO-ARK-ay], Propator, and Bythus), who had a female counterpart named Ennœa (also known as Charis or Sige). The main branch of Gnostics Irenæus exposed were the Valentinians. The Valentinians taught that there were thirty Aeons existing in pairs who reproduced successive pairs of male and female Aeons. The last of them was Sophia, or Knowledge, who broke with tradition of ignorance and passionately desired to know the original Aeon. Eventually, a being known as the Demiurge, who emanated from Sophia, erred greatly by creating the physical universe. Gnostics identified this foolish Demiurge as the Creator God of the Old Testament. A common Christianization of Gnosticism was to portray the God of the Old Testament as evil and Jesus and His Father as good and wise beings who were trying to rescue the people of the world from their physical natures. Salvation, according to Gnostics, was the enlightenment one gains by learning the elaborate names and stories behind their beliefs. The enlightenment would allow people to escape the physical world and join a purely spiritual realm where they would be reconnected with the original Aeon.

Irenæus did not just expose the overcomplicated Valentinian teachings though. He described the beliefs of other Gnostic groups, whose names and stories were different from the Valentinians. Most of the groups were nameless, but Irenæus also exposed the teachings of Gnostics named Secundus, Epiphanes, Ptolemy, Marcus, Simon the Magician (from Acts 8), Saturninus, Basilides, Carpocrates, Marcellina Cerinthus, the Ebionites, the Nicolaitans (from Revelation 2:6, 15), Cerdo, Marcion, and the Encratites. Irenæus hoped, by exposing the “mutually inconsistent opinions” of the Gnostics, to persuade anyone from being seduced by their teaching.

If the mere exposure of the confusing overcomplexity in Book One did not persuade Irenæus’s readers to avoid Gnostic teaching, Book Two provided an argument that the Gnostics used poor logic to arrive at their conclusions. For example, the very idea of polytheism, or there being multiple gods, is absurd, for if neither of two gods are perfect, then there must be a reality or god greater than they are. Likewise, if angels created the world apart from the will of the greatest Aeon, then the greatest Aeon is not really that good, wise, or careful. Irenæus also pointed out that the teachings of the Gnostics were inconsistent with the “Rule of Faith,” which was the consistent and comprehensive teaching about the Trinity, creation, salvation, and other doctrines. Shifting the burden of proof to the Gnostics, he exposes the emptiness of their system, showing that they copied their ideas from preexisting stories but just changed the names. They also made extensive use of math to show that numbers which could be added together to arrive at thirty were proof enough that there were 30 Aeons. One of the chief theological contributions of Irenæus in his Against Heresies was his doctrine of the atonement called the recapitulation theory. The recapitulation theory suggests that all parts of Jesus’ life on the earth, including any physical suffering he endured, are indispensable to the salvation of other human beings. The recapitulation theory emphasizes God’s role as the redeemer of creation, not one who merely wanted to help the spirits imprisoned inside people’s flesh to escape. The second book concludes with a refutation of the absurdity of the migration of souls where people might spiritually transfer from one form to another. 

Finally, books three, four, and five investigate specific passages of Scripture to demonstrate Gnosticism’s broad and deep contradictions with an historical understanding of Scripture. Throughout the work, Irenæus shows how faulty the interpretations of Scripture by the Gnostics are. No sane scholar would read a piece of literature like the Gnostics read the Scriptures. However, in the final three books, Irenæus reminds his readers of passages in every section of the Scriptures and in which ways the passages contradict the most prominent claims of Gnostic theology. By the end of the fifth book, Irenæus has well demonstrated that the historical events portrayed by the Scriptures, especially physical creation and the physical life, death, and resurrection of Jesus, are essential to a proper understanding of the truth, Christianity, and God Himself. Irenæus engages in a negative apologetic, or defense of the faith, when he dismantles the heretical claims of the Gnostics; but he also engages in a positive apologetic when he gives biblical evidence for specific features of God and salvation that directly contradict Gnostic claims. In the end, based on the Scriptures and the consistent teaching of the church handed down from Jesus through clear lines of Apostles and their disciples, the truth of the Gospel can be, and is, clearly known by the church around the known world. Irenæus not only exposed the fallacies of Gnosticism in his chief work, Against Heresies, but he used ideas and language that later theologians would use and develop as they formulated their own theological expressions in writings, creeds, and liturgical formulae.

  1.  Eusebius, Ecclesiastical History, 5:1.
  2.  A Dictionary of Early Christian Beliefs, s.v. “Gnostics, Gnosticism” (Peabody, MA: Hendrickson Publishers, 1998).
  3. Cleveland Cox, “Introductory Note to Irenæus Against Heresies” in The Apostolic Fathers with Justin Martyr and Irenæus in Ante-Nicene Fathers, American edition (Peabody, MA: Hendrickson, 1995), 313.
  4.  Irenæus, Against Heresies, preface, 1.
  5.  Irenæus, Against Heresies, 1:1.
  6.  Irenæus, Against Heresies, 1:1-11.
  7.  Irenæus, Against Heresies, 1:11.
  8.  Irenæus, Against Heresies, 1:12.
  9.  Irenæus, Against Heresies, 1:13-22.
  10.  Irenæus, Against Heresies, 1:23.
  11.  Irenæus, Against Heresies, 1:24.
  12.  Irenæus, Against Heresies, 1:25.
  13.  Irenæus, Against Heresies, 1:26.
  14.  Irenæus, Against Heresies, 1:27.
  15.  Irenæus, Against Heresies, 1:28.
  16.  Irenæus, Against Heresies, 1:11.
  17.  Irenæus, Against Heresies, 2:1.
  18.  Irenæus, Against Heresies, 2:2. 
  19.  Irenæus, Against Heresies, 2:9.
  20.  Irenæus, Against Heresies, 2:14. 
  21.  Irenæus, Against Heresies, 2:22.
  22.  Irenæus, Against Heresies, 2:31.
  23.  Irenæus, Against Heresies, 2:33-34.
  24.  Irenæus, Against Heresies, 2:27.