Ante-Nicene Fathers Volume 5
Cyprian: Epistle LXXII
Yet another letter on the baptism performed by "heretics" (which, to remind ourselves, can mean either theological heretics or schismatics). In this case Novatian is the "heretic" in question who is baptizing believers his schismatic assembly. Cyprian notes that this is not really a concern of the "true" church, until those baptized by Novatian apply for admission: "it does not in any wise matter to us what the enemies of the church do, so long as we ourselves hold a regard for our power and the steadfastness of reason and truth."
Cyprian then proceeds through several topics and occurrences related to this question, including that of the Marcionites. He notes that in that case, the schismatics themselves were heretics as well, and of course their baptism didn't count because they denied the Trinity.
Again, we see that what is hanging Cyprian up is his doctrine of (almost) baptismal regeneration. (We see that it's not really that awful doctrine which would develop later, since the substance of faith is still critical.) So long as Cyprian believes water baptism is a necessary cause of salvation, he's going to get caught on questions of form and confuse the visible church with the invisible church. Fortunately, Cyprian also believes that Scripture is the final authority here, and that to which we must continually appeal to sort this issue out. ("Hence it is in vain that some who are overcome by reason oppose to us custom, as if custom were greater than truth; or as if that were not to be sought after in spiritual matters which has been revealed as the better by the Holy Spirit." [i.e. Scripture])
Overall, this letter is long. Like, really long. But it's also worth reading because here you get the root arguments for baptismal regeneration and all the errors of polity, practice, and theology that spring from that. And again, we can at least agree with many of Cyprian's concerns: the practice of baptism should be taken seriously and Scripturally; the church should be unified rather than divided; baptism should be done only by believers [i.e. performed by believers], if it is done improperly it should be done correctly.
This is also the letter where we get Cyprian's famous (and true!) maxim: "there is no salvation outside the church." The context is a discussion of the baptism of martyrs. What do we do with someone who is executed for being a Christian but has not been baptized? The answer is that those who are true Christians who are so executed, are to be considered "baptized in his own blood." That is, faithful believers who do not have the chance to be baptized before martyrdom may be counted as having been baptized anyway, while "even this baptism does not benefit a heretic." Those who deny the true faith, even if executed by the government as "Christians" are still outside the church and so not counted as "baptized." (Though if they reject their heresy and embrace the true faith but don't get baptized before martyrdom, they're still in!) In that sense, of course, we can all agree with Cyprian's statement about there being no salvation outside the church. As we've seen repeatedly, Cyprian's goal is maximum generosity when trying to figure this stuff out without sacrificing the holiness or faithful confession of the church. And that too, hopefully we can all be on board with.
There is, however, one open lie at the end of the letter: "these things, dearest brother, I have briefly written to you." No Cyprian, you haven't written briefly at all.