It is a remarkable phenomenon in nature that, if you put a plant into a large, wide pot or tub, it grows very much at the roots; they thicken, they give out many ramifications, but the tree itself does not grow much in height, and only yields few and small leaves and flowers. But if it is planted in a small pot, then the roots are small, but the plant itself grows rapidly in height and yields beautiful leaves and flowers (if it is the nature of the plant to produce flowers). Is it not the same with man? When he lives in full liberty, in abundance and prosperity, then he grows in body and does not grow in spirit, does not bring forth fruits — good works; whilst when he lives in straightness, in poverty, sickness, misfortune, and afflictions, in a word, when his animal nature is crushed, then he grows spiritually, bears flowers of virtue, ripens and brings forth rich fruits. This is why the path of those who love God is a narrow one.
St. John of Krondstat
On Good Works