Almost all bodily excellences alter with age, and while wisdom alone increases all things else decay. Fasts and vigils and almsdeeds become harder. So also do sleeping on the ground, moving from place to place, hospitality to travellers, pleading for the poor, earnestness and steadfastness in prayer, the visitation of the sick, manual labor to supply money for alms-giving. All acts, in short, of which the body is the medium decrease with its decay.

Now, there are young men still full of life and vigor who, by toil and burning zeal, as well as by holiness of life and constant prayer to the Lord Jesus, have obtained knowledge. I do not speak of these, or say that in them the love of wisdom is cold, for this withers in many of the old by reason of age. What I mean is that youth, as such, has to cope with the assaults of passion, and amid the allurements of vice and the tinglings of the flesh is stifled like a fire among green boughs, and cannot develop its proper brightness. But when men have employed their youth in commendable pursuits and have meditated on the law of the Lord day and night, they learn with the lapse of time, fresh experience and wisdom come as the years go by, and so from the pursuits of the past their old age reaps a harvest of delight. — Letter LII. To Nepotian.