a. About Persons in the State of Exercising Perfection

30. One can concede about the first that, when they are performing acts that belong to them by reason of such state of perfection (as teaching, judging, preaching), both sorts of lies [sc. useful and jocose] would be a mortal sin in their case, for they take away the authority and usefulness of the doctrine being preached, according to the remark of Augustine, based on three letters to Jerome [Letters 26 ch.3 nn.3-4, 40 ch.3 n.3, 82 ch.2 n.21], “If lies, however jocose, had been introduced in the Sacred Scriptures, nothing of solidity would remain in them.” For instance, if a prelate while preaching introduced a jocose lie, nothing of solidity remains in his teaching. For anyone can be in doubt about anything said by him as he can be in doubt about anyone else. Or the reason the hearer would not assent to the jocose lie would be a like reason not to assent to anything else that was said. And thus the authority of the teachers of the Church in their teaching will perish, and also their utility for the people listening. The same for solemn judgment or solemn teaching. And I mean this, that the lie is not perceived as said apart from the act of judging or teaching. For while someone is sitting in judgment it is possible to mix some scam in it, which from the manner of speaking is known not to belong to the judgment.

31. It seems, however, that a single jocose or useful lie does not impede the authority of a judge or teacher, but such a lie often repeated or the custom of thus lying does. But then, since according to the laws [Gregory IX Decrees I tit.6 ch.34] ‘a twice repeated act introduces a custom’, it follows that the second act is a mortal sin and not the first, although however the second is altogether like the first (as it seems) in all its circumstances.

32. Whatever may be true of one or several such lies in teaching and judging, at least in other acts it would not be a mortal sin, once the idea of scandal is removed.