Against Two Letters of the Pelagians

It would be too long if I were to seek to mention everything which the holy Ambrose said and wrote against this heresy of the Pelagians, which was to arise so long afterwards; not indeed with a view to answer them, but with a view to declare the catholic faith, and to build up men in it. Moreover, I neither could nor ought to mention all those things which Cyprian, most glorious in the Lord, wrote in his letters, whereby it is shown how this which we hold is the true and truly Christian and catholic faith, as it was delivered of old by the Holy Scriptures, and so retained and kept by our fathers and even to this time, in which these heretics have attempted to destroy it, and as it will hereafter by God's good will be retained and kept.

For that these things and things of this kind were thus delivered to Cyprian, and by Cyprian, is testified by the testimonies produced from his letters; and that thus they were maintained up to our times is shown by these things which Ambrose wrote about these matters before these heretics had begun to rage, and catholic ears had shuddered at their profane novelties which are everywhere; and that thus, moreover, they shall be maintained hereafter, was declared with sufficient vigour partly by the condemnation of such opinions as these, partly by their correction. For whatever they may dare to mutter against the sound faith of Cyprian and Ambrose, I do not think that they will break out into such a madness as to dare to call those noted and memorable men of God, Manicheans.