As long as you live, you will be subject to change, whether you will it or not - now glad, now sorrowful; now pleased, now displeased; now devout, now undevout; now vigorous, now slothful; now gloomy, now merry. But a wise man who is well taught in spiritual labor stands unshaken in all such things, and heeds little what he feels, or from what side the wind of instability blows.

Autore: Thomas à Kempis