Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 2

Chapter 2.—3.  Whence, then, is a man to be cleansed who receives baptism, when the conscience of the giver is polluted without the knowledge of him who is to receive it?  Especially when he goes on to say, "For he who receives faith from the faithless receives not faith, but guilt."  There stands before us one that is faithless ready to baptize, and he who should be baptized is ignorant of his faithlessness:  what think you that he will receive?  Faith, or guilt?  If you answer faith, then you will grant that it is possible that a man should receive not guilt, but faith, from him that is faithless; and the former saying will be false, that "he who receives faith from the faithless receives not faith, but guilt."  For we find that it is possible that a man should receive faith even from one that is faithless, if he be not aware of the faithlessness of the giver.  For he does not say, He who receives faith from one that is openly and notoriously faithless; but he says, "He who receives faith from the faithless receives not faith, but guilt;" which certainly is false when a person is baptized by one who hides his faithlessness.  But if he shall say, Even when the faithlessness of the baptizer is concealed, the recipient receives not faith from him, but guilt, then let them rebaptize those who are well known to have been baptized by men who in their own body have long concealed a life of guilt, but have eventually been detected, convicted, and condemned.