For good habit of body in boys is the foundation of a good old age. For as in fine weather we ought to lay up for winter, so in youth one ought to form good habits and live soberly so as to have a reserve stock of strength for old age. Yet ought we to husband the exertions of the body, so as not to be wearied out by them and rendered unfit for study.
 Plutarch, Moralia (c. 100 AD). copy citation

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Author Plutarch
Source Moralia
Topic youth strength
Date c. 100 AD
Language English
Reference
Note Translated by Arthur Richard Shilleto
Weblink http://www.gutenberg.org/files/23639/23639-h/23639-h.htm

Context

“Exercise also ought not to be neglected, but we ought to send our boys to the master of the gymnasium to train them duly, partly with a view to carrying the body well, partly with a view to strength. For good habit of body in boys is the foundation of a good old age. For as in fine weather we ought to lay up for winter, so in youth one ought to form good habits and live soberly so as to have a reserve stock of strength for old age. Yet ought we to husband the exertions of the body, so as not to be wearied out by them and rendered unfit for study. For, as Plato says,23 excessive sleep and fatigue are enemies to learning. But why dwell on this? For I am in a hurry to pass to the most important point. Our lads must be trained for warlike encounters, making themselves efficient in hurling the javelin and darts, and in the chase.” source