Tu qui in Latinis mussitas, et testudineo gradu moveris potius, quam incedis: vel Graece debes scribere, ut apud homines Graeci sermonis ignaros aliena scire videaris: vel si Latina tentaveris, ante audire grammaticum, ferulae manum subtrahere, et inter parvulos ἀθηνογέρων artem loquendi discere. quamvis Croesos quis spiret et Darios, litterae marsupium non sequuntur. sudoris comites sunt et laboris; sociae ieiuniorum, non saturitatis; continentiae, non luxuriae. Demosthenes plus olei quam vini expendisse dicitur, et omnes opifices nocturnis semper vigiliis praevenisse. quod ille in una littera fecit exprimenda, ut a cane rho disceret, tu in me criminaris, quare homo ab homine Hebraeas litteras didicerim. inde est quod quidam inerudite sapientes remanent, dum nolunt discere quod ignorant.
(Jerome, Apologia Adversus Libros Rufini 1.17)
You who can hardly do more than mutter in Latin, and who rather creep like a tortoise than walk, ought either to write in Greek, so that among those who are ignorant of Greek you may pass for one who knows a foreign tongue; or else, if you attempt to write Latin, you should first have a grammar-master, and flinch from the ferule, and begin again as an old scholar among children to learn the art of speaking. Even if a man is bursting with the wealth of Crœsus and Darius, letters will not follow the money-bag. They are the companions of toil and of labour, the associates of the fasting not of the full-fed, of self-mastery not of self-indulgence. It is told of Demosthenes that he consumed more oil than wine, and that no workman ever shortened his nights as he did. He for the sake of enunciating the single letter Rho was willing to take a dog as his teacher; and yet you make it a crime in me that I took a man to teach me the Hebrew letters. This is the sort of wisdom which makes men remain unlearned: they do not choose to learn what they do not know. (tr. William Henry Fremantle)