48 It seems to you an odious thing to say that baptism was given to some after John had baptized them, and yet that baptism is not to be given to men after heretics have baptized them; but it may be said with equal justice to be an odious thing that baptism was given to some after John had baptized them, and yet that baptism is not to be given to men after intemperate persons have baptized them. I name this sin of intemperance rather than others, because those in whom it reigns are not able to hide it: and yet what man, even though he be blind, does not know how many addicted to this vice are to be found everywhere? And yet among the works of the flesh, of which it is said that they who do them shall not inherit the kingdom of God, the apostle places this in an enumeration in which heresies also are specified: “Now the works of the flesh,” he says, “are manifest, which are these: adultery, fornication, uncleanness, lasciviousness, idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, envyings, murders, drunkenness, revellings, and such like; of the which I tell you before, as I have also told you in time past, that they who do such things shall not inherit the kingdom of God.” Baptism, therefore, although it was administered after John, is not administered after a heretic, on the very same principle according to which, though administered after John; it is not administered after an intemperate man: for both heresies and drunkenness are among the works which exclude those who do them from inheriting the kingdom of God. Does it not seem to you as if it were a thing intolerably unseemly, that although baptism was repeated after it had been administered by him who, not even moderately drinking wine, but wholly refraining from its use, prepared the way for the kingdom of God, and yet that it should not be repeated after being administered by an intemperate man, who shall not inherit the kingdom of God? What can be said in answer to this, but that the one was the baptism of John, after which the apostle administered the baptism of Christ; and that the other, administered by an intemperate man, was the baptism of Christ? Between John Baptist and an intemperate man there is a great difference, as of opposites; between the baptism of Christ and the baptism of John there is no contrariety, but a great difference. Between the apostle and an intemperate man there is a great difference; but there is none between the baptism of Christ administered by an apostle, and the baptism of Christ administered by an intemperate man. In like manner, between John and a heretic there is a great difference, as of opposites; and between the baptism of John and the baptism of Christ which a heretic administers there is no contrariety, but there is a great difference. But between the baptism of Christ which an apostle administers, and the baptism of Christ which a heretic administers, there is no difference. For the form of the sacrament is acknowledged to be the same even when there is a great difference in point of worth between the men by whom it is administered.
49. But pardon me, for I have made a mistake in wishing to convince you by arguing from the case of an intemperate man administering baptism; for I had forgotten that I am dealing with a Rogatist, not with one bearing the wider name of Donatist. For among your colleagues who are so few, and in the whole number of your clergy, perhaps you cannot find one addicted to this vice. For you are persons who hold that the name Catholic is given to the faith not because communion of those who hold it embraces the whole world, but because they observe the whole of the Divine precepts and the whole of the sacraments; you are the persons in whom alone the Son of man when He comes shall find faith, when on the earth He shall find no faith, forasmuch as you are not earth and on the earth, but heavenly and dwelling in heaven! Do you not fear, or do you not observe that “God resists the proud, but gives grace to the humble”? Does not that very passage in the Gospel startle you, in which the Lord says, “When the Son of man comes, shall He find faith in the earth?” Immediately thereafter, as if foreseeing that some would proudly arrogate to themselves the possession of this faith, He spoke to some who trusted in themselves that they were righteous, and despised others, the parable of the two men who went up to the temple to pray, the one a Pharisee, and the other a publican. The words which follow I leave for yourself to consider and to answer. Nevertheless examine more minutely your small sect, to see whether not so much as one who administers baptism is an intemperate man. For so widespread is the havoc wrought among souls by this plague, that I am greatly surprised if it has not reached even your infinitesimal flock, although it is your boast that already, before the coming of Christ, the one good Shepherd, you have separated between the sheep and the goats.
Source: Letters (New Advent)