June 28 + Saint Irenaeus

Irenaeus of Lyons was a second-century bishop and writer in present-day France. He is best known for laying the foundations of Christian theology and for defending Christian orthodoxy, especially the reality of Christ’s human incarnation, against the set of heresies known as Gnosticism.

While some of Irenaeus’ most important writings have survived, the details of his life are not as well-preserved. He was born in the Eastern half of the Roman Empire, likely in Smyrna, around the year 130. As a young man he heard the preaching of the early bishop (and eventual martyr) Saint Polycarp, who had been personally instructed by the Apostle John.

Irenaeus eventually became a priest, and served in the Church of Lyons during a difficult period in the late 170s. During this time of state persecution and doctrinal controversy, Irenaeus was sent to Rome to provide Pope St. Eleutherius with a letter about the heretical movement known as Montanism. After returning to Lyons, Irenaeus became the city’s second bishop, following the martyrdom of his predecessor Saint Pothinus.

In the course of his work as a pastor and evangelist, the second Bishop of Lyon came up against various heretical doctrines and movements, many of which sounded a common note in their insistence that the material world was evil and not part of God’s original plan. The proponents of these ideas often claimed to be more deeply “enlightened” or “spiritual” than ordinary Christians, on account of their supposed secret knowledge (or “gnosis”).

Irenaeus recognized this movement, in all its forms, as a direct attack on the Catholic faith. The Gnostics’ disdain for the physical world was irreconcilable with the Biblical doctrine of creation, which stated that God had made all things according to his good purpose. Gnostics, by contrast, saw the material world as the work of an evil power, crediting God only with the creation of a higher and purely spiritual realm.

In keeping with its false view of creation, Gnosticism also distorted the concept of redemption. The Church knew Christ as the savior of the world: redeeming believers’ bodies and souls, and investing creation with a sacramental holiness. Gnostics, meanwhile, saw Jesus merely as saving souls from the physical world in which they were trapped. Gnostic “redemption” was not liberation from sin, but a supposed promise of release from the material world.

Irenaeus refuted the Gnostic errors in his lengthy book “Against Heresies,” which is still studied today for its historical value and theological insights. A shorter work, the “Proof of the Apostolic Preaching,” contains Irenaeus’ presentation of the Gospel message, with a focus on Jesus Christ’s fulfillment of Old Testament prophecies.