Irenaeus was born in Asia Minor around 140 a.d. In his youth, he was a disciple of Saint Polycarp of Smyrna, who in turn had been a follower of Saint John the Apostle. Thus he had a vital, personal link to the "handing on" of the truth about Jesus Christ from those who knew Him and were commissioned to be His witnesses.
Irenaeus travelled to Rome and to Southern Gaul and eventually became bishop in the city of Lyons. In Rome he first encountered the strange phenomenon of "Christian Gnosticism," and he battled against it throughout most of his episcopal ministry in Lyons. Many Christians in Rome in the middle of the second century had become captivated by the theories of a charismatic preacher named Valentinus. After an unsuccessful attempt to get himself elected pope in 140, Valentinus broke openly from the Church and began to develop his own Christian gnostic sect. The general tendencies of the gnostic movement — its stress on esoteric and secret wisdom, its radical dualism between spirit and matter, and its hierarchy of divinities — resulted in a very peculiar interpretation of biblical revelation and the life of Jesus Christ.
For Valentinus and his disciples, the God of the Old Testament is not the Ultimate Divine being, but an inferior and rebellious deity who created the material world for his own evil purposes. Another more powerful deity called “Christ" was sent from the pleroma (the "society" of divine beings) to teach the truth and offer deliverance to lesser spirits who were trapped in this material prison. He inhabited the man Jesus — he certainly did not become incarnate — and by this means he taught secret doctrines to his initiates (the apostles). Needless to say, the Christ-deity (being no fool) abandoned the man Jesus before the messiness of the Passion got started.
Behind the crassness and silliness of this highly imaginative distortion of Christianity we can recognize a perennial heretical principle: the denial of the historical drama of the redemption in favor of some purely theoretical or interpretive scheme that supposedly reveals to us the "real" significance of Christ and Christianity. Irenaeus wrote his masterpiece — his treatise Against the Heresies — to combat Valentinianism and other gnosticisms that made their way up the Italian peninsula into Gaul. Throughout this great work, he contrasts the "secret knowledge" of the gnostics with the tradition handed down from the Apostles and preserved in the Church.
Irenaeus stresses the consistency and reliability of this tradition, linked as it is to the real Jesus Christ of history. At the same time he meditates more deeply on the unity of the Divine plan and the centrality of Christ’s redeeming action. It is one God who creates all things visible and invisible and who recreates them in Christ. The world that is created through the agency of the Divine Word is recapitulated — brought again "under the headship" — of the Word made flesh, who, by coming into the world, embraces history and consecrates it to God.
Thus Irenaeus gave eloquent testimony to a theme that was original to Christianity: the unity and purpose of history centered on the Incarnate Word.
Here is a brief quotation from Saint Irenaeus himself:
Here is a brief quotation from Saint Irenaeus himself:
"We have learned from none others the plan of our salvation, than from those through whom the Gospel has come down to us, which they did at one time proclaim in public, and, at a later period, by the will of God, handed down to us in the Scriptures, to be the ground and pillar of our faith." The witness of the apostolic tradition attests to "the only true and steadfast Teacher, the Word of God, our Lord Jesus Christ, who did, through His transcendent love, become what we are, that He might bring us to be even what He is Himself."
~Saint Irenaeus