Augustine of Hippo, Against Two Letters of the Pelagians IV.29: The Testimonies of Ambrose Against the Pelagians and First of All Concerning Original Sin

Chapter 29 [XI.]—The Testimonies of Ambrose Against the Pelagians and First of All Concerning Original Sin.

But now also to the most glorious martyr Cyprian, let me add, for the sake of more amply confuting these men, the most blessed Ambrose; because even Pelagius praised him so much as to say that in his writings could be found nothing to be blamed even by his enemies. Since, then, the Pelagians say that there is no original sin with which infants are born, and object to the catholics the guilt of the Manichean heresy, who withstand them on behalf of the most ancient faith of the Church, let this catholic man of God, Ambrose, praised even by Pelagius himself in the truth of the faith, answer them concerning this matter. When he was expounding the prophet Isaiah, he says: “Christ was, therefore, without spot, because He was not stained even in the usual condition itself of birth.” And in another place in the same work, speaking of the Apostle Peter, he says: “He offered himself, which he thought before to be sin, asking for himself that not only his feet but his head also should be washed, because he had directly understood that by the washing of the feet, for those who fell in the first man, the filth of the obnoxious succession was abolished.” Also in the same work he says: “It was preserved, therefore, that of a man and woman, that is, by that mingling of bodies, no one could be seen to be free from sin; but He who is free from sin is free also from this kind of conception.” Also writing against the Novatians he says: “All of us men are born under sin. And our very origin is in corruption, as you have it read in the words of David, ‘For lo, I was conceived in iniquities; and in sins hath my mother brought me forth.’” Also in the apology of the prophet David, he says: “Before we are born we are spotted with contagion, and before the use of light we receive the mischief of that origin. We are conceived in iniquity.” Also speaking of the Lord, he says: “It was certainly fitting that He who was not to have the sin of a bodily fall, should feel no natural contagion of generation. Rightly, therefore, David with weeping deplored in himself these defilements of nature, and the fact that the stain had begun in man before his life.” Again, in the Ark of Noah he says: “Therefore by one Lord Jesus the coming salvation is declared to the nations; for He only could be righteous, although every generation should go astray, nor for any other reason than that, being born of a virgin, He was not at all bound by the ordinance of a guilty generation. ‘Behold,’ he says, ‘I was conceived in iniquities; and in sins has my mother brought me forth;’ he who was esteemed righteous beyond others so speaks. Whom, then, should I now call righteous unless Him who is free from those chains, whom the bonds of our common nature do not hold fast?” Behold, this holy man, most approved, even by the witness of Pelagius, in the catholic faith, condemned the Pelagians who deny original sin with such evidence as this; and yet he does not with the Manicheans deny either God to be the Creator of those who are born, or condemn marriage, which God ordained and blessed.