Laudator Temporis Acti

Diogenes Laertius 6.2.70 (on Diogenes the Cynic; tr. R.D. Hicks):

He used to affirm that training was of two kinds, mental and bodily: the latter being that whereby, with constant exercise, perceptions are formed such as secure freedom of movement for virtuous deeds; and the one half of this training is incomplete without the other, good health and strength being just as much included among the essential things, whether for body or soul. And he would adduce indisputable evidence to show how easily from gymnastic training we arrive at virtue. For in the manual crafts and other arts it can be seen that the craftsmen develop extraordinary manual skill through practice. Again, take the case of flute-players and of athletes: what surpassing skill they acquire by their own incessant toil; and, if they had transferred their efforts to the training of the mind, how certainly their labours would not have been unprofitable or ineffective.

διττὴν δ’ ἔλεγε εἶναι τὴν ἄσκησιν, τὴν μὲν ψυχικήν, τὴν δὲ σωματικήν· ταύτην καθ’ ἣν ἐν γυμνασίᾳ συνεχεῖς γινόμεναι φαντασίαι εὐλυσίαν πρὸς τὰ τῆς ἀρετῆς ἔργα παρέχονται. εἶναι δ’ ἀτελῆ τὴν ἑτέραν χωρὶς τῆς ἑτέρας, οὐδὲν ἧττον εὐεξίας καὶ ἰσχύος ἐν τοῖς προσήκουσι γενομένης, ὡς περὶ τὴν ψυχὴν καὶ περὶ τὸ σῶμα. παρετίθετο δὲ τεκμήρια τοῦ ῥᾳδίως ἀπὸ τῆς γυμνασίας ἐν τῇ ἀρετῇ καταγίνεσθαι· ὁρᾶν τε γὰρ ἔν τε ταῖς τέχναις βαναύσοις καὶ ταῖς ἄλλαις οὐ τὴν τυχοῦσαν ὀξυχειρίαν τοὺς τεχνίτας ἀπὸ τῆς μελέτης πεποιημένους τούς τ’ αὐλητὰς καὶ τοὺς ἀθλητὰς ὅσον ὑπερφέρουσιν ἑκάτεροι τῇ ἰδίᾳ πονήσει τῇ συνεχεῖ, καὶ ὡς οὗτοι εἰ μετήνεγκαν τὴν ἄσκησιν καὶ ἐπὶ τὴν ψυχήν, οὐκ ἂν ἀνωφελῶς καὶ ἀτελῶς ἐμόχθουν.

This is fragment 291 of Diogenes the Cynic in Gabriele Giannantoni, ed., Socraticorum Reliquiae, Vol. II (Naples: Bibliopolis, 1983), pp. 525-526.