"A wise man stands unshaken in all such things"- Thomas a Kempis

“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.” 
― Thomas à Kempis, The Imitation of Christ