Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 3

Chapter 3.—4.  There are two propositions, moreover, which we affirm,—that baptism exists in the Catholic Church, and that in it alone can it be rightly received,—both of which the Donatists deny.  Likewise there are two other propositions which we affirm,—that baptism exists among the Donatists, but that with them it is not rightly received, of which two they strenuously confirm the former, that baptism exists with them; but they are unwilling to allow the latter, that in their Church it cannot be rightly received.  Of these four propositions, three are peculiar to us; in one we both agree.  For that baptism exists in the Catholic Church, that it is rightly received there, and that it is not rightly received among the Donatists, are assertions made only by ourselves; but that baptism exists also among the Donatists, is asserted by them and allowed by us.  If any one, therefore, is desirous of being baptized, and is already convinced that he ought to choose our Church as a medium for Christian salvation, and that the baptism of Christ is only profitable in it, even when it has been received elsewhere, but yet wishes to be baptized in the schism of Donatus, because not they only, nor we only, but both parties alike say that baptism exists with them, let him pause and look to the other three points.  For if he has made up his mind to follow us in the points which they deny, though he prefers what both of us acknowledge, to what only we assert, it is enough for our purpose that he prefers what they do not affirm and we alone assert, to what they alone assert.  That baptism exists in the Catholic Church, we assert and they deny.  That it is rightly received in the Catholic Church, we assert and they deny.  That it is not rightly received in the schism of Donatus, we assert and they deny.  As, therefore, he is the more ready to believe what we alone assert should be believed, so let him be the more ready to do what we alone declare should be done.  But let him believe more firmly, if he be so disposed, what both parties assert should be believed, than what we alone maintain.  For he is inclined to believe more firmly that the baptism of Christ exists in the schism of Donatus, because that is acknowledged by both of us, than that it exists in the Catholic Church, an assertion made alone by the Catholics.  But again, he is more ready to believe that the baptism of Christ exists also with us, as we alone assert, than that it does not exist with us, as they alone assert.  For he has already determined and is fully convinced, that where we differ, our authority is to be preferred to theirs.  So that he is more ready to believe what we alone assert, that baptism is rightly received with us, than that it is not rightly so received, since that rests only on their assertion.  And, by the same rule, he is more ready to believe what we alone assert, that it is not rightly received with them, than as they alone assert, that it is rightly so received.  He finds, therefore, that his confidence in being baptized among the Donatists is somewhat profitless, seeing that, though we both acknowledge that baptism exists with them, yet we do not both declare that it ought to be received from them.  But he has made up his mind to cling rather to us in matters where we disagree.  Let him therefore feel confidence in receiving baptism in our communion, where he is assured that it both exists and is rightly received; and let him not receive it in a communion, where those whose opinion he has determined to follow acknowledge indeed that it exists, but say that it cannot rightly be received.  Nay, even if he should hold it to be p. 414 a doubtful question, whether or no it is impossible for that to be rightly received among the Donatists which he is assured can rightly be received in the Catholic Church, he would commit a grievous sin, in matters concerning the salvation of his soul, in the mere fact of preferring uncertainty to certainty.  At any rate, he must be quite sure that a man can be rightly baptized in the Catholic Church, from the mere fact that he has determined to come over to it, even if he be baptized elsewhere.  But let him at least acknowledge it to be matter of uncertainty whether a man be not improperly baptized among the Donatists, when he finds this asserted by those whose opinion he is convinced should be preferred to theirs; and, preferring certainty to uncertainty, let him be baptized here, where he has good grounds for being assured that it is rightly done, in the fact that when he thought of doing it elsewhere, he had still determined that he ought afterwards to come over to this side.