Letters (Epistulae)

it is perhaps too much for you to read them, but the summary of them can perhaps be read to you, which I believe my brother and fellow-bishop Optatus possesses; or, if he does not have it, he can very easily receive it from the church of Sitifis, since even this book is perhaps already burdensome to your cares due to its length.

7 For this happened to the Donatists, which happened to the accusers of the holy Daniel. For just as the laws were turned against those men as the lions were, by which they wished to crush the innocent, except that because of the mercy of Christ these laws are rather for their benefit, which seem adverse to them, since many have been corrected by them and are corrected daily and give thanks that they have been corrected and liberated from that furious ruin. And those who hated, now love, and they acknowledge that the laws were most wholesome to them, and as much as they detested them in their insanity, they rejoice as much when their health is restored, and they are stirred up with a similar love alongside us—so that we may labor together—to stand against the others with whom they were going to perish, so that they may not perish. For a physician is bothersome to a raging, delirious patient, and a father to an undisciplined son, the former by binding, the latter by whipping, yet both by loving. If, however, they neglect them and allow them to perish, that false gentleness is rather cruel. For if a horse and a mule, which have no understanding, resist with bites and kicks the men by whom their wounds are to be treated, and although men are often in danger between their teeth and hooves and are sometimes troubled, they do not abandon them, however, until through the pains and medicinal annoyances they bring them back to health, how much more...

Scriptural references: Dan 6:24; Ps 31:9 (alluding to the lack of understanding of a mule).