85 Vincentius of Thibari said: "We know that heretics are worse than heathens. If they, being converted, wish to come to God, they have assuredly a rule of truth, which the Lord by His divine precept committed to the apostles, saying, 'Go, lay on hands in my name, cast out devils.' and in another place, 'Go, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.' Therefore, first by the laying on of hands in exorcism, secondly by regeneration in baptism, they may come to the promises of Christ; but my judgment is that in no other way should this be done."
86. By what rule he asserts that heretics are worse than heathens I do not know, seeing that the Lord says, "If he neglect to hear the Church, let him be unto you as a heathen man and a publican." Is a heretic worse even than such? I do not gainsay it. I do not, however, allow that because the man himself is worse than a heathen, that is, than a Gentile and pagan, therefore whatever the sacrament contains that is Christ's is mingled with his vices and character, and perishes through the corruption of such admixture. For if even those who depart from the Church, and become not the followers but the founders of heresies, have been baptized before their secession, they continue to have baptism, although, according to the above rule, they are worse than heathens; for if on correction they return, they do not receive it, as they certainly would do if they had lost it. It is therefore possible that a man may be worse than a heathen, and yet that the sacrament of Christ may not only be in him, but be not a whit inferior to what it is in a holy and righteous man. For although to the extent of his powers he has not preserved the sacrament, but done it violence in heart and will, yet so far as the sacrament's own nature is concerned, it has remained unhurt in its integrity even in the man who despised and rejected it. Were not the people of Sodom heathens, that is to say, Gentiles? The Jews therefore were worse, to whom the Lord says, "It shall be more tolerable for the land of Sodom in the day of judgment than for you;" and to whom the prophet says, "You have justified Sodom," that is to say, in comparison with you Sodom is righteous. Shall we, however, maintain that on this account the holy sacraments which existed among the Jews partook of the nature of the Jews themselves—those sacraments which the Lord Himself also accepted, and sent the lepers whom He had cleansed to fulfill them, of which when Zacharias was administering them, the angel stood by him, and declared that his prayer had been heard while he was sacrificing in the temple? These same sacraments were both in the good men of that time, and in those bad men who were worse than are the heathens, seeing that they were ranked before the Sodomites for wickedness, and yet those sacraments were perfect and holy in both.
87. For even if the Gentiles themselves could have anything holy and right in their doctrines, our saints did not condemn it, however much the Gentiles themselves were to be detested for their superstitions and idolatry and pride, and the rest of their corruptions, and to be punished with judgment from heaven unless they submitted to correction. For when Paul the apostle also was saying something concerning God before the Athenians, he adduced as a proof of what he said, that certain of them had said something to the same effect, which certainly would not be condemned but recognized in them if they should come to Christ. And the holy Cyprian uses similar evidence against the same heathens; for, speaking of the magi, he says, "The chief of them, however, Hostanes, asserts both that the form of the true God cannot be seen, and also that true angels stand beside His seat. In which Plato also agrees in like manner, and, maintaining the existence of one God, he calls the others angels or demons. Hermes Trismegistus also speaks of one God, and confesses that He is incomprehensible, and past our powers of estimation." If, therefore, they were to come to the perception of salvation in Christ, it surely would not be said to them, This that you have is bad, or false; but clearly it would deservedly be said, Though this in you is perfect and true, yet it would profit nothing unless ye came to the grace of Christ. If, therefore, anything that is holy can be found and rightly approved in the very heathens, although the salvation which is of Christ is not yet to be granted to them, we ought not, even though heretics are worse than they, to be moved to the desire of correcting what is bad in them belonging to themselves, without being willing to acknowledge what is good in them of Christ. But we will set forth from a fresh preface to consider the remaining judgments of this Council.
Source: On Baptism, Against the Donatists (New Advent)