"It was whilst Eve was yet a virgin that the word crept in, which was the framer of death. Into a Virgin in like manner, must be introduced the Word of God who was the builder up of life, so that by the same sex, whence had come our ruin, might come also our recovery, to salvation. Eve had believed the serpent, Mary believed Gabriel. The fault which the one committed by believing, the other by believing blotted out." (De Carne Christi, 17.)
Before Tertullian penned those words in Africa, the same thought had found expression in the writings of St. Irenaeus, Bishop of Lyons, in Gaul.
"The knot of Eve's disobedience obtained its unloosing through the obedience of Mary; for that which Eve a virgin bound by her unbelief, Mary a Virgin unbound by her faith."
"As Eve was seduced by an angel's word to shun God after she had transgressed His Word, so Mary, also by an Angel's word, had the glad tidings given her, that she might bear God, obeying His Word. And if the former had disobeyed God, yet the latter was persuaded to obey God, that Mary the Virgin might come to the rescue of the virgin Eve. And as the human race was bound to death by means of a virgin, it is saved by means of a Virgin ; the poise of the balance being restored—a virgin's disobedience is saved by the obedience of a Virgin." (Haer v. 19)