Petrarch, Secretum 3.14:
Francesco: It’s not coming to me right now, and I’m afraid to draw forth my ignorance into view. And so I would rather be silent about what I think is true.
Augustinus: This alone you have chosen wisely and modestly. For in every speech, especially in one important and doubtful, one should pay attention less to what is said than to what is not said, because the praise that comes from good speech cannot equal the chastisement that comes from bad speech. Therefore, keep in mind that fame is nothing but speech divulged by one person and then sprinkled about through the mouths of the multitude.
Non occurrit id quidem ad presens et ignota in medium proferre metuo. Ideoque, quod esse verius opinor, siluisse maluerim.
Prudenter hoc unum et modeste. Nam in omni sermone, gravi presertim et ambiguo, non tam quid dicatur, quam quid non dicatur attendendum est. Neque enim par ex bene dictis laus et ex male dictis reprehensio est. Scito igitur famam nichil esse aliud quam sermonem de aliquo vulgatum ac sparsum per ora multorum.