In the second century, in a Roman colony at the western edge of the known world, a bishop sat down and wrote five long books to defend the simplest truth of the Christian faith. The body is good. The world is good. Salvation does not mean escaping from creation. It means being made fully alive in it. His name was Irenaeus.
Who
Irenaeus was born around the year 130 in Smyrna, on the western coast of what is now Turkey. As a boy he sat at the feet of the city’s old bishop, Polycarp, and listened. Polycarp was already an old man by then. He had been a disciple of Saint John the Apostle. He used to tell the boys of the city what John had told him, in his own words, about what the Lord had said and done. So Irenaeus, by the time he was ten or twelve, was one step removed from John and two steps removed from Christ. He never forgot a single sentence.
As a young man he went west, to Gaul, what we now call France. The Greek-speaking Christian community of Lyons had grown up there along the trade routes of the Rhone valley, a small frontier outpost of the Church. In 177, while Irenaeus was away in Rome carrying a letter, a persecution broke over the city. The aged bishop Pothinus, ninety years old, was beaten to death in prison. Forty-eight Christians were killed in the arena over the course of a few terrible days, including a young slave girl named Blandina, who endured days of torture and whom the records describe as hung on a stake like the figure on a cross while the beasts let loose in the arena would not touch her, until at last she was killed before a bull. When Irenaeus returned, the church had no shepherd. They chose him.
He served Lyons as bishop for the rest of his life, more than twenty years. His chief work, written in five books and known as Adversus Haereses, Against the Heresies, was directed at the Gnostics, the religious movement of his age that taught that the body was a prison, that creation was the mistake of a lesser god, that the Old Testament was the work of a hostile deity, and that salvation meant escaping flesh altogether. Irenaeus answered them line by line. Patiently, exhaustively, with the calm of a man who has actually known the apostles’ disciples. He is, by long tradition, the father of Catholic theology.
He is believed to have been martyred around the year 202, in another wave of persecution under the Emperor Septimius Severus. He was canonised soon after, and in 2022 Pope Francis declared him a Doctor of the Church under the title Doctor of Unity, because everything he wrote, against the heresies of his own day and across the divisions of his own city, was for the unity of the Christian people.
Two other gifts of his theology are worth naming here. He gave the Church its first long teaching on the figure of Mary, the new Eve. Just as Eve, who had been virgin and disobedient, had brought sin into the world, so Mary, virgin and obedient, undid that knot. What the virgin Eve had bound by her unbelief, the Virgin Mary loosed by her faith. The image is his, written in Lyons around the year 180, and the Church has carried it ever since. He also taught what came to be called the doctrine of recapitulation, that Christ, in becoming a human being, lived through every stage of human life and gathered all of it, every age and every wound, into Himself, so that He could heal it from the inside. There is no part of being a human person, from infancy to death, that He did not first take on and bless.
The original voice
Gloria enim Dei vivens homo, vita autem hominis visio Dei.
Irenaeus, Against the Heresies, Book IV, ch. 20 (c. 180 AD)
The glory of God is the living human, and the life of the human is the vision of God.
What he meant
The Gnostics of his time had a low view of the human being. The body was a cage. The flesh was a curse. Birth was a tragedy from which only a secret knowledge could rescue the soul. Salvation meant escape. The visible world, with all its trees and skin and rain and ordinary bread, was something to be left behind.
Irenaeus stood squarely against this. He insisted, with steady patience, that God made the world good and called it good. That He made the human being in His own image, gave him a body, breathed His own life into him, and meant the whole thing, body and soul together, for glory.
And so came the sentence. The glory of God is the living human. Not the disembodied soul. Not the human escaped from the world. The living human. Flesh and blood, walking on the earth, breathing in His sight. When God looks at us going about our small days, eating bread and washing dishes and praying badly and loving our families, He is glorified by the very fact that we are alive in Him. That is the answer to the Gnostic. That is what creation is for.
And then the second half. And the life of the human is the vision of God. We exist for Him. To be alive in the fullest sense, to be most ourselves, is to see Him face to face. The first half answers the question, what is the human being for? The second half answers, what is the human being for forever?
And underneath it all is his great image of recapitulation. Christ did not come, Irenaeus says, simply to teach us or to forgive us. He came to live through every stage of human life, to sanctify each one from the inside. He was once a child, so that childhood would be holy. He was once a young man, so that the years between boyhood and the cross would be holy. He died, so that even our dying would be a thing taken up into His own. There is no part of being human He did not first inhabit. The whole human road has been walked already by God Himself.
Voices that came after
Eighteen centuries after Irenaeus wrote his five books in Lyons, a Polish pope took up the same conviction with all of the weight of the modern papacy behind it. Saint John Paul II quoted the Irenaean line again and again, in encyclicals, in catecheses, in homilies, in conversations with young people. He had lived through Nazi occupation and Soviet ideology, two systems built on a contempt for the human being. He had seen, in his own century, what happens to a society that forgets that the person is sacred.
Christ, the new Adam, in the very revelation of the mystery of the Father and of His love, fully reveals man to himself and brings to light his most high calling.
Gaudium et Spes 22 (Second Vatican Council, 1965) — the line Saint John Paul II quoted more often than any other.
The deepest reason for the dignity of the human being, John Paul wrote elsewhere, is the call to communion with God. Irenaeus, eighteen hundred years earlier, said the same thing in nine Latin words. The life of the human is the vision of God.
And in the twentieth century, a French Jesuit named Henri de Lubac spent years recovering Irenaeus for a Church that had nearly forgotten him. De Lubac saw, in the second-century bishop of Lyons, the answer to the spiritual sickness of the modern West, which had quietly come to believe that the world could get on perfectly well without God. He wrote that the human person, separated from his destiny in God, becomes a stranger to himself.
Man cannot organise the world for himself without God. Without God he can only organise it against man.
Henri de Lubac, The Drama of Atheist Humanism (1944)
That, too, is the lesson of Irenaeus. Take God out of the picture, and the human being does not become freer. He becomes smaller, and finally cruel. Keep God in the picture, and the human being is glorified just by being alive in His sight.
Why it still matters
The Gnostic temptation has not gone away. It comes back in every generation in a new dress. Sometimes it is contempt for the body. Sometimes it is the cult of the body. Sometimes it is the belief that the visible world is a sham and only the inward life is real. Sometimes it is the opposite belief, that only the visible world is real and the soul is a leftover word from a religious age.
To all of it Irenaeus answers with the same sentence. You are flesh and you are spirit, and God made both. You are not a soul trapped in a body, and you are not a body with no soul. You are a human being, made by Him, loved by Him, kept alive by Him, and meant for His vision forever.
If you have lived long enough to feel old in the body, or tired in the spirit, or unsure what your small days are for, Irenaeus will tell you. They are for this. To be alive, today, in His sight, is already glory. You do not have to earn it. You only have to keep walking.
A line to carry into the week
The glory of God is the human being fully alive.