[24] for it is really marvellous when any one touches the soul, like a lyre tuned in musical principles, not with sharp and flat sounds, but with an accurate knowledge of contrary tones, and employing only the best, not sounding any too loudly, nor on the other hand letting any be too weak, so as to impair the harmony of the virtues and of those things which are good by nature, and when he, preserving it in an equal condition plays and sings melodiously;