Plutarch De recta ratione audiendi 8

[8] One ought therefore to strip off the superfluity and inanity from the style, and to seek after the fruit itself, imitating not women that make garlands, but the bees. For those women, culling flowerclusters and sweet-scented leaves, intertwine and plait them, and produce something which is pleasant enough, but short-lived and fruitless; whereas the bees in their flight frequently pass through meadows of violets, roses, and hyacinths, and come to rest upon the exceeding rough and pungent thyme, and on this they settle close, and when they have got something of use, they fly away home to their own special work. In such wise, then, the sincere and single-minded student ought to regard flowery and dainty language and theatrical and spectacular subject matter as the pasturage of drones who practise the popular lecture; these he should leave alone and use all diligence to sound the deep meaning of the words and the intention of the speaker, drawing from it what is useful and profitable, and remembering that he has not come to a theatre or music-hall, but to a school and classroom with the purpose of amending his life by what is there said. Hence it follows that in making his examination and forming his judgement of the lecture he should begin with himself and his own state of mind, endeavouring to estimate whether any one of his emotions has become less intense, whether any one of his troubles weighs less heavily upon him, whether his confidence and his high purpose have become firmly rooted, whether he has acquired enthusiasm for virtue and goodness. As a matter of course, when he rises to leave the barber’s shop, he stands by the mirror and feels his head, examining the cut of his hair and the difference made by its trimming; so on his way home from a lecture or an academic exercise, it would be a shame not to direct his gaze forthwith upon himself and to note carefully his own spirit, whether it has put from it any of its encumbrances and superfluities, and has become lighter and more cheerful. For, as Ariston says, neither a bath nor a discourse is of any use unless it removes impurity.