
The truth of this was shown when the Word of God became man, assimilating Himself to man and man to Himself, so that, by His resemblance to the Son, man might become precious to the Father. For in times past it was said that man was made in the image of God, but not shown, because the Word, in whose image man was made, was still invisible. That is why man lost the likeness so easily. But when the Word of God was made flesh, He confirmed both things: He showed the true image, when He Himself became what His image was; and He restored and made fast the likeness, making man like the invisible Father through the visible Word. Against Heresies V 16, 2
In His immeasurable love, He became what we are in order to make us what He is. Against Heresies V, preface
[The Gnostics] reject the commixture of the heavenly wine. They only want to be the water of this world and will not admit God into commixture with them. And so they remain in the Adam conquered and cast out of Paradise. They fail to see that, as at the beginning of our formation in Adam the breath of life which comes from God was united to what had been formed, animated man, and showed him to be a rational animal, so, at the end, the Word of the Father and the Spirit of God, united to the ancient substance of Adam’s formation, made man living and perfect, capable of knowing the perfect Father. This was so that, as in the ‘animal man’ we all die, so in the ‘spiritual man’ we might all be made alive (cf 1 Cor 15:22). Adam at no time escaped the Hands of God [the Son and the Spirit], to whom the Father said, ‘Let us make man in our image and likeness’ (Gen 1:26). That is why, at the end, ‘not by the will of the flesh or the will of a man’, but by the good pleasure of the Father, the Hands of God made the living Man, so that Adam might come into the image and likeness of God. Against Heresies V 1, 3
There was no other way for us to receive incorruptibility and immortality than to be united to incorruptibility and immortality. But how could we be united to incorruptibility and immortality without incorruptibility and immortality first becoming what we are, the perishable putting on imperishability, the mortal putting on immortality (cf 1 Cor 15:54), ‘so that we might receive adoption as sons’ (Gal 4:5)? Against Heresies III 19, 1
The first formed man, Adam, received his substance from the untilled and still virgin earth (‘for God had not caused it to rain upon the earth, and there was no man to till the ground’, Gen 2:5) and was fashioned by the Hand of God, that is, the Word of God (for ‘all things were made through Him’, John 1:3, and ‘God took dust from the earth and formed man’, Gen 2:7). Similarly, the Word, recapitulating Adam in Himself, very fittingly received from Mary, who was still a virgin, the birth which made recapitulation possible . . . Why did God not take dust again? Why did He make the formation come from Mary? Precisely so that there was not some different formation, that it was not some different handiwork which was saved, that it was the very same one which was recapitulated, the likeness being preserved. Against Heresies III 21, 10
Had He received nothing from Mary [as the Gnostics believe], He would never have taken the foods which come from the earth, the foods by which the body taken from the earth is nourished. Nor would He have felt hunger after fasting, like Moses and Elijah, for forty days, if His body had not been seeking its proper nourishment. Nor would John his disciple have written: ‘Jesus, wearied by the journey, sat down’ (John 4:6), nor would David have prophesied of Him: ‘They added to the pain of my wounds’ (cf Ps 68:27). Nor would He have wept over Lazarus, nor would He have sweated drops of blood, nor would blood and water have flowed from His pierced side. For these are all signs of flesh taken from the earth, the flesh which the Lord recapitulated in Himself, in order to save His own handiwork. Against Heresies III 22, 2
{All quotes are taken from Fr. John Saward’s translation of St. Irenaeus as they are found in The Scandal of the Incarnation.}

