Nicene and Post-Nicene Fathers: Series I/Volume IV/Donatist Controversy/Answer to the Letters of Petilian, the Donatist/Book I/Chapter 26

28.&#160; But it is possible that you may expect of me that I should go on to refute what he has introduced about Manich&#230;us.&#160; Now, in respect of this, the only thing that offends me is that he has censured a most pestilent and pernicious error—I mean the heresy of the Manich&#230;ans—in terms of wholly inadequate severity, if indeed they amount to censure at all, though the Catholic Church has broken down his defenses by the strongest evidence of truth. &#160; For the inheritance of Christ, established in all nations, is secure against heresies which have been shut out from the inheritance; but, as the Lord says, "How can Satan cast out Satan?" so how can the error of the Donatists have power to overthrow the error of the Manich&#230;ans?