On the Posterity of Cain (106-110)

for all other animals, having a broken utterance in their voice, by this and by an incessant change of tones alone give pleasure to our ears. But man, being furnished by nature with the means not only of speaking but also of singing articulately, charms both the sense of hearing and the mind, soothing the one with his song and influencing the other with ideas;

for, as an instrument, if it be given into the hands of a man who has no skill as a musician, is inharmonious, but if given to a musician it becomes harmonious according to the skill that is in him. So in the same manner speech, when put in motion by a worthless mind, is inharmonious; but, when it is put in motion by a virtuous mind, it is found to be very melodious.

A lyre, indeed, or any similar instrument, if it be not struck by some one, is silent; and speech, too, if it be not struck by the principal part, that is to say, the mind, is of necessity tranquil. And, again, as musical instruments are transposed and adapted to an infinite number of mixtures of airs, so also speech corresponds to them, becoming an interpreter of things;

for who would converse in a similar manner with parents and children, being by nature the slave of the one, and by birth the master of the others? And who, again, would talk in the same manner to brothers or cousins; or, in short, to near and to distant relations? Who, again, could do so to friends and to strangers, to fellow citizens and to foreigners, though there may be no great difference in point of fortune, or nature, or age

And why need one cite an incredible variety of persons to whom speech varies itself, so as at one time to assume one character and at another time another? For it would not interpret great things and small, numerous things and rare, private and public matters, sacred and profane affairs, or old and new events in the same manner; but would use, in each case, language appropriate to the number, or importance, or magnitude of the affairs under discussion; at one time elevating itself to a lofty style, and at another time, on the contrary, confining and humbling itself.