40. Moreover, I would have learned men to know that the authors of our Scriptures use all those forms of expression which grammarians call by the Greek name tropes, and use them more freely and in greater variety than people who are unacquainted with the Scriptures, and have learnt these figures of speech from other writings, can imagine or believe. Nevertheless those who know these tropes recognize them in Scripture, and are very much assisted by their knowledge of them in understanding Scripture. But this is not the place to teach them to the illiterate, lest it might seem that I was teaching grammar. I certainly advise, however, that they be learnt elsewhere, although indeed I have already given that advice above, in the second book namely, where I treated of the necessary knowledge of languages. For the written characters from which grammar itself gets its name (the Greek name for letters being "grammata") are the signs of sounds made by the articulate voice with which we speak. Now of some of these figures of speech we find in Scripture not only examples (which we have of them all), but the very names as well: for instance, allegory, enigma, and parable. However, nearly all these tropes which are said to be learnt as a matter of liberal education are found even in the ordinary speech of men who have learnt no grammar, but are content to use the vulgar idiom. For who does not say, "So may you flourish? " And this is the figure of speech called metaphor. Who does not speak of a fish-pond in which there is no fish, which was not made for fish, and yet gets its name from fish? And this is the figure called catachresis.