Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 29

Chapter 29.—66.  Petilianus said:  "But to pass rapidly through these minor points:  can he be said to lay down the law who is not a magistrate of the court? or is what he lays down to be considered law, when in the character of a private person he disturbs public rights?  Is it not rather the case that he not only involves himself in guilt, but is held to be a forger, and that which he composes a forgery?"

67.  Augustin answered:  What if your private person, whom you deem a forger, were to set forth to any one the law of the emperor?  Would not the man, when he had compared it with the law of those who have the genuine law, and found it to be identically the same, lay aside all care about the source from which he had obtained it, and consider only what he had obtained?  For what the forger gives is false when he gives it of his own falseness; but when something true is given by any person, even though he be a forger, yet, although the giver be not truthful, the gift is notwithstanding true.