Book I · Chapter 55 — Ambrose Witnesses that Perfect Purity is Impossible to Human Nature.

He ought, moreover, carefully to note that, in the very same context from which he quoted that passage of Ambrose's, which seemed so satisfactory for his purpose, he also said this: "To be spotless from the beginning is an impossibility to human nature." In this sentence the venerable Ambrose does undoubtedly predicate feebleness and infirmity of that natural "capacity," which Pelagius refuses faithfully to regard as corrupted by sin, and therefore boastfully extols. Beyond question, this runs counter to this man's will and inclination, although it does not contravene the truthful confession of the apostle, wherein he says: "We too were once by nature the children of wrath, even as others." For through the sin of the first man, which came from his free will, our nature became corrupted and ruined; and nothing but God's grace alone, through Him who is the Mediator between God and men, and our Almighty Physician, succours it. Now, since we have already prolonged this work too far in treating of the assistance of the divine grace towards our justification, by which God co-operates in all things for good with those who love Him, and whom He first loved --giving to them that He might receive from them: we must commence another treatise, as the Lord shall enable us, on the subject of sin also, which by one man has entered into the world, along with death, and so has passed upon all men, setting forth as much as shall seem needful and sufficient, in opposition to those persons who have broken out into violent and open error, contrary to the truth here stated.

Book II.

On Original Sin.

Wherein Augustin shows that Pelagius really differs in no respect, on the question of original sin and the baptism of infants, from his follower Coelestius, who, refusing to acknowledge original sin and even daring to deny the doctrine in public, was condemned in trials before the bishops--first at Carthage, and afterwards at Rome; for this question is not, as these heretics would have it, one wherein persons might err without danger to the faith. Their heresy, indeed, aimed at nothing else than the very foundations of Christian belief. He afterwards refutes all such as maintained that the blessing of matrimony is disparaged by the doctrine of original depravity, and an injury done to God himself, the Creator of man who is born by means of matrimony.