A READING FROM THE TREATISE AGAINST HERESIES BY ST IRENAEUS
The Lord came visibly to his own domain, and was sustained by his own creation which he himself sustains in being. By his obedience upon a tree he reversed the disobedience shown because of another tree. The seduction to which the betrothed virgin Eve had miserably fallen victim was remedied by the truth happily announced by the angel to Mary, another betrothed virgin.
As Eve, seduced by an angel, turned away from God by disobedience to his word, so Mary, receiving the good news from an angel, bore God in her womb in obedience to his word; and as Eve had been led to disobey God, so Mary was persuaded to obey him. Thus the Virgin Mary became the advocate of the virgin Eve.
Christ recapitulated all things in himself, including our war against the enemy. He challenged and defeated him who in the beginning had taken us captive in Adam, and he crushed his head in accordance with God’s words to the serpent in Genesis: I will put enmity between you and the woman, and between your offspring and her offspring, he shall lie in wait for your head, and you shall lie in wait for his heel.
From that time on, he who was to be born of a virgin in the likeness of Adam was foretold as the one who would lie in wait for the serpent’s head. This is the descendant to whom Paul refers when he says in his letter to the Galatians: The law of works was in force until the coming of the descendant to whom the promise had been made. Paul is still more explicit when he says in the same letter: When the fullness of time had come, God sent his Son, born of a woman. The enemy would not have been defeated fairly if his vanquisher had not been a man born of a woman, because it was through a woman that he gained mastery over the human race in the beginning, and set himself up as our adversary.
That is why the Lord proclaims himself the Son of Man, who recapitulates in himself that first man from whom the race born of woman was formed: as by a man’s defeat our race fell into the bondage of death, so also by a man’s victory we were to rise again to life.
St Irenaeus, Adv. Haer. Lib.5,19,1; 20,2; 21,1 (SC 153, 248-250,260-264), fr. Word in Season 1