17 What answer they can give about the followers of Maximianus whom they have received, they cannot divine. If they say, "Those we received were innocent," the answer is obvious, "Then you had condemned the innocent." If they say, "We did it in ignorance," then you judged rashly (just as you passed a rash judgment on the traditors), and your declaration was false that "you must know that they were condemned by the truthful voice of a plenary Council." For indeed the innocent could never be condemned by a voice of truth.
If they say, "We did not condemn them," it is only necessary to cite the Council, to cite the names of bishops and states alike. If they say, "The Council itself is none of ours," then we cite the records of the proconsular province, where more than once they quoted the same Council to justify the exclusion of the followers of Maximianus from the basilicas, and to confound them by the din of the judges and the force of their allies. If they say that Felicianus of Musti, and Prætextatus of Assavæ, whom they afterwards received, were not of the party of Maximianus, then we cite the records in which they demanded, in the courts of law, that these persons should be excluded from the Council which they held against the party of Maximianus.
If they say, "They were received for the sake of peace," our answer is, "Why then do ye not acknowledge the only true and full peace? Who urged you, who compelled you to receive a schismatic whom you had condemned, to preserve the peace of Donatus, and to condemn the world unheard, in violation of the peace of Christ?" Truth hems them in on every side. They see that there is no answer left for them to make, and they think that there is nothing left for them to do; they cannot find out what to say. They are not allowed to be silent. They had rather strive with perverse utterance against truth, than be restored to peace by a confession of their faults.
Source: On Baptism, Against the Donatists (New Advent)