Nicene and Post-Nicene Fathers, Vol. V:
A Treatise Against Two Letters of the...: Chapter 6

Chapter 6.—Not Death Alone, But Sin Also Has Passed into Us by Means of Adam.

In that particular, indeed, wherein they say “that death passed to us by Adam, not sins,” they have not the Manicheans as their adversaries: since they, too, deny that original sin from the first man, at first of pure and upright body and spirit, and afterwards depraved by free will, subsequently passed and passes as sin into all with death; but they say that the flesh was evil from the beginning, and was created by an evil spirit and along with an evil spirit; but that a good soul—a portion, to wit, of God—for the deserts of its defilement by food and drink, in which it was before bound up, came into man, and thus by means of copulation was bound in the chain of the flesh. And thus the Manicheans agree with the Pelagians that it was not the guilt of the first man that passed into the human race—neither by the flesh, which they say was never good; nor by the soul, which they assert comes into the flesh of man with the merits of its own defilements with which it was polluted before the flesh. But how do the Pelagians say “that only death passed upon us by Adam’s means”? For if we die because he died, but he died because be sinned, they say that the punishment passed without the guilt, and that innocent infants are punished with an unjust penalty by deriving death without the deserts of death. This, the catholic faith has known of the one and only mediator between God and man, the man Christ Jesus, who condescended to undergo death—that is, the penalty of sin—without sin, for us. As He alone became the Son of man, in order that we might become through Him sons of God, so He alone, on our behalf, undertook punishment without ill deservings, that we through Him might obtain grace without good deservings. Because as to us nothing good was due so to Him nothing bad was due. Therefore, commending His love to them to whom He was about to give undeserved life, He was willing to suffer for them an undeserved death. This special prerogative of the Mediator the Pelagians endeavour to make void, so that this should no longer be special in the Lord, if Adam in such wise suffered a death due to him on account of his guilt, as that infants, drawing from him no guilt, should suffer undeserved death. For although very much good is conferred on the good by means of death, whence some have fitly argued even “of the benefit of death;” yet from this what can be declared except the mercy of God, since the punishment of sin is converted into beneficent uses?