12 I urge, I beg, I exhort, I warn, for it is a grief to me, that you who were an example of unusual piety, who were conspicuous for clemency, who would not suffer single offenders to be put in peril, should not mourn that so many have perished. Though you have waged battle most successfully, though in other matters, too, you are worthy of praise, yet piety was ever the crown of your actions. The devil envied that which was your most excellent possession. Conquer him while you still possess that wherewith you may conquer. Do not add another sin to your sin by a course of action which has injured many.
Source: Letters (New Advent)