37 What shall we say of what he himself advanced in his epistle, that "Quodvultdeus, having been convicted of two adulteries, and cast out from among you, was received by those of our party?" What then (I would speak without prejudice to this man, who proved his case to be a good one, or at least persuaded men that it was so), when such men among you, being as yet undetected, administer baptism, what is received at their hands—faith, or guilt? Surely not faith, because they have not the conscience of one who gives in holiness to cleanse the conscience of the recipient.
But yet not guilt either, in virtue of that added word: "For he that has received his faith wittingly from one that is faithless, receives not faith but guilt." But when men were baptized by those of whom I speak, they were surely ignorant what sort of men they were. Furthermore, not receiving faith from their baptizers, who had not the conscience of one that gives in holiness, and not receiving guilt, because they were baptized not knowing but in ignorance of their faults, they therefore remained without faith and without guilt.
They are not, therefore, in the number of men of such abandoned character. But neither can they be in the number of the faithful, because, as they could not receive guilt, so neither could they receive faith from their baptizers. But we see that they are reputed by you in the number of the faithful, and that no one of you declares his opinion that they ought to be baptized, but all of you hold valid the baptism which they have already received. They have therefore received faith; and yet they have not received it from those who had not the conscience of one that gives in holiness, to cleanse the conscience of the recipient.
Whence then did they receive it? This is the point from which I make my effort; this is the question that I press most earnestly; to this I do most urgently demand an answer.
Source: Answer to Letters of Petilian, Bishop of Cirta (New Advent)