Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 47

Chapter 47.—57.  Furthermore, in like manner as those who denied the resurrection of the dead could in no way defend themselves from the evil consequences which the apostle proved to follow from their premises, in order to refute their error, saying, "Then is not Christ raised," with the other conclusions of similar atrocity, unless they changed their opinions, and acknowledged that there was a resurrection of the dead; so is it necessary that you should change your opinion, and cease to rest on man the hope of those who are baptized, if you do not wish to have imputed to you what we say for your refutation and correction, that they are justified with greater holiness who are baptized by undetected evil men than those that are baptized by men that are genuinely and manifestly good.  For if you make your first assertion, see what I say, unless some one shall suppress this a second time, and make out that I have entertained the opinion which I quote for your refutation and correction.  See what I lay down as my premiss, from which hangs the statement which I shall subsequently make:  If you rest the hope of those who are to be baptized on the man by whom they are baptized, and if you maintain, as Petilianus wrote, that the man who baptizes is the origin and root and head of him that is baptized; if you receive as the good tree the good man who baptizes, and as his good fruit the man who has been baptized by him; then you put it into our heads to ask from what origin he springs, from what root he shoots up, to what head he is joined, from what tree he is born, who is baptized by an undetected bad man?  For to this inquiry, belongs also the following, to which I have over and over again maintained that Petilianus has given no reply:  By what means is a man to be cleansed who receives baptism while he is ignorant of the stain upon the conscience of him that gives but not in holiness? for this conscience of him that gives, or of him that gives in holiness, Petilianus wishes to be the origin, root, head, seed, tree from which the sanctification of the baptized has its existence,—springs, begins, sprouts forth, is born.