Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 11

Chapter 11.—25.  Petilianus said:  "Yet some will be found to say, We are not the sons of a traditor.  Any one is the son of that man whose deeds he imitates.  For those are most assuredly sons, and at the same time bear a strong resemblance to their parents, who are born in the likeness of their parents, not only as being of their flesh and blood, but in respect of their characters and deeds."

26.  Augustin answered:  A little while ago you were saying nothing contrary to us, now you even begin to say something in our favor.  For this proposition of yours binds you to as much as this, that if you shall fail to-day to convict us, with whom you are arguing, of being traditors and murderers, and anything else with which you charge us, you will then be wholly powerless to hurt us by any charge of the kind which you may prove against those who have gone before us.  For we cannot be the sons of those to whose deeds our actions bear no resemblance.  And see to what you have committed yourself.  If you should be so successful as to convict some man, even of our own times, and living with us, of any guilt of the kind, that is in no way to the prejudice of all the nations of the earth who are blessed in the seed of Abraham, by separating yourself from whom you are found to be guilty of sacrilege.  Accordingly, unless (as is altogether impossible) you are acquainted with all men that exist throughout the world, and have not only made yourself familiar with all their characters and deeds, but have also proved that they are as bad as you describe, you have no ground for reproaching all the world, which is among the saints, with parentage of I know not what description, to whom you prove that they are like.  Nor will it help you at all, even if you are able to show that those who are not of the same character take the holy sacraments in common with those who are.  In the first place, because you ought yourselves to look at those with whom you celebrate those sacraments, to whom you give them, from whom you receive them, and whom you would be unwilling to have cast up against you as a reproach.  And again, if all those are the sons of Judas, who was the devil among the apostles, who imitate his deeds, why do we not call those of the sons of the apostles who make such men partakers, not in their own deeds, but in the sacraments of the Lord, as the apostles partook of the supper of the Lord in company with that traitor? and in this way they are very different from you, who cast in the teeth of men who are striving for the preservation of unity the very thing that you do to the rending asunder of unity.