Had the feast of SS Peter and Paul not been transferred from tomorrow, last Sunday would have been the memoria of St Irenaeus of Lyons (c. 135-200)
Irenaeus was confronted by the challenge of Gnosticism – a highly sophisticated form of syncretistic esotericism which had latched onto Christianity and in which guru-like teachers initiated their followers into complex and symbolic belief-systems filled with cosmic mediator-figures and organized around the dualistic idea that salvation consisted in the liberation of the soul from the prison of the body.
Irenaeus opposed the Gnostic emphasis on private revelation to inspired teachers who then passed on their esoteric teaching to the enlightened by developing more explicitly than anyone before him the ideas of (i) the unity of the Church, (ii) the unity of the Faith (determined by the “rule of faith”), (iii) the identity of the Church as the locus of faith and grace and true teaching, and (iv) the apostolicity of the Church (for Irenaeus, the only valid teaching was that which could be traced back to one of the apostolic sees and especially the see of Rome).
Against the Gnostic teaching that the Christian life was about the liberation of the soul from the flesh, Irenaeus proclaimed the salvation of the whole human being – the healing, integration, perfection and (to use Patristic terminology) deification of body and soul, flesh and spirit. God created human beings to be in the image of God, to be filled with divine grace, and, ultimately, to behold the vision of God. Humanity is perfected in the person of Christ, who assumes human nature with all its materiality and fleshliness.
Irenaeus emphasizes (like Cyril of Alexandria) the personal unity of Christ, who is the divine person of the Son/Word who becomes fully human (without detriment to his divinity) – a true God-man, and not a human being existing in moral union with God or (at the other extreme) a divine person masquerading as a human being.
As perfect man, the incarnate Son fulfils in himself mankind’s destiny to be in the image of God, to be grace-filled, and to behold the glory of the Father. He “recapitulates” in himself the whole of mankind, passing through the various phases of birth, infancy, childhood, human suffering, etc, living the perfect human life in each of its successive stages.
He gathers up into his own person the story of Adam, the history of mankind, and the entirety of God’s plan for the redemption and perfection of everything, and becomes both the climax of human history up to that point and also the inauguration of the new creation (this is very much a development of the theology of Ephesians 1:3-10 and Colossians 1:10-20).
The God-man’s perfect obedience to the Father reveals the new covenant, makes atonement for the sins of mankind, undoes the damage caused by Adam’s fall, and creates a new kind of human existence which is characterized by a fully redeemed flesh, a healed will, a capacity for that “grace-fulness” which the Church Fathers call “deification”, and an orientation to behold the vision of God.
Christians share in this redemption through the Eucharist and through the power of the Holy Spirit. Irenaeus understands Christ’s presence in the Eucharist very literally and realistically. The bread and wine truly become the Body and Blood of the God-man, and through them the God-man incorporates us into himself (recapitulatio also denotes the idea of bringing everyone and everything under the headship of Christ as in Eph. 1:10), communicating to us his new kind of human existence, his redeemed flesh and healed will, his grace-fulness – in short, giving us a share in his deified humanity.