“In Irenaeus (died c. AD 202) we meet a theologian who understands that the Christian conception of salvation is inextricable from a proper theology of creation. He was enabled to make his great contribution, perhaps the greatest of all, to the doctrine of creation because of the crisis that met him in the form of those heresies grouped under the name of Gnosticism. As we have seen, Gnostics saw salvation in terms of the imparting of knowledge, and knowledge of such a kind as to require a radical distinction between the material and spiritual worlds. In contrast, Irenaeus saw it as the outcome of incarnation and its fruit in a life in community centred on the bread and wine of the Lord’s Supper, a life which as a consequence embraced the importance of life in the body.

“Out of Irenaeus’ preoccupations there developed two motifs which set the tone for later developments. The first is his strong affirmation of the goodness of everything created by God, matter included. The Gnostics had in various ways denied the goodness of the material world. Although Irenaeus does not assert what we shall later describe as the ontological homogeneity of the creation, he writes in opposition to platonist tendencies to teach that there are two entirely different kinds of reality, the spiritual or intellectual and the sensible or material. ‘He (God) conferred on spiritual things a spiritual and invisible nature, on supercelestial things a supercelestial, on angels an angelical, on animals an animal . . . on all, in short, a nature suitable to the character of the life assigned them . . . ’ The basis of Irenaeus’ affirmative attitude to the whole created order is christological. If God in his Son takes to himself the reality of human flesh, then nothing created, and certainly nothing material, can be downgraded to unreality, semi-reality or treated as fundamentally evil, as in the Manichaeans version of Gnosticism. . . . 

“We shall see more and more clearly as we trace episodes in the history of the doctrine of creation that the place given, or not given, to the Trinity is determinative of the character of any doctrine of creation. There can and have been doctrines of creation in the Christian tradition which have been scarcely trinitarian in their shaping, with the result that their articulation contains elements which tend to undermine essential components of the teaching. For Irenaeus, two aspects are decisive. The first is that his trinitarian matrix enables him to develop a theology of mediation, always the heart of the matter. As is well known, Irenaeus frequently says that God creates by means of his two hands, the Son and the Spirit. This enables him to give a clear account of how God relates to that which is not God: of how the creator interacts with his creation. The second aspect reveals the other side of this same reality, the freedom of God in relation to the created universe. Because God creates by means of his own Son and Spirit, he is unlike the deities of the Gnostics and the One of neoplatonism in that he does not require beings intermediate between himself and the world in order to achieve his ends. That is, because the Son and the Spirit are God, to create by means of his two hands means that God is himself creating. This is accordingly a theology of mediation which breaks through Hellenic doctrines of degrees of being. There do not, on this account, need to be intermediate beings between God and the world, because the Son and the Spirit mediate between the divine and the created.”

— from Colin E. Gunton, The Triune Creator: A Historical and Systematic Study (William B. Eerdmans Publishing Company, 1998)

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