As in the Olympic Games it is not the most attractive and the strongest who are crowned, but those who compete (since it is from this group that winners come), so in life it is those who act rightly who will attain what is noble and good.

[ὥσπερ δ᾽ Ὀλυμπίασιν οὐχ οἱ κάλλιστοι καὶ ἰσχυρότατοι στεφανοῦνται ἀλλ᾽ οἱ ἀγωνιζόμενοι （τούτων γάρ τινες νικῶσιν）, οὕτω καὶ τῶν ἐν τῷ βίῳ καλῶν κἀγαθῶν οἱ πράττοντες ὀρθῶς ἐπήβολοι γίνονται.]

Aristotle (384-322 BC) Greek philosopher

Nicomachean Ethics [Ἠθικὰ Νικομάχεια], Book 1, ch. 9 (1.9, 1099a.4) (c. 325 BC) [tr. Crisp (2000)]
    (Source)

(Source (Greek)). Alternate translations:

And as at the Olympic games it is not the finest and strongest men who are crowned, but they who enter the lists, for out of these the prize-men are selected; so too in life, of the honourable and the good, it is they who act who rightly win the prizes.
[tr. Chase (1847), ch. 6]

For as at the Olympic games it is not the fairest and the strongest who are crowned, but they that run -- for some of these it is that win the victory -- so too, among the noble and good in life, it is they that act rightly who become masters of life's prize.
[tr. Williams (1869)]

As in the Olympian games it is not the most beautiful and strongest persons who receive the crown, but they who actually enter the lists as combatants -- for it is some of these who become victors -- so it is they who act rightly that attain what is noble and good in life.
[tr. Welldon (1892), ch. 9]

And as at the Olympic games it is not the fairest and strongest who receive the crown, but those who contend (for among these are the victors), so in life, too, the winners are those who not only have all the excellences, but manifest these in deed.
[tr. Peters (1893)]

And as in the Olympic Games it is not the most beautiful and the strongest that are crowned but those who compete (for it is some of these that are victorious), so those who act win, and rightly win, the noble and good things in life.
[tr. Ross (1908)]

And just as at the Olympic games the wreaths of victory are not bestowed upon the handsomest and strongest persons present, but on men who enter for the competitions -- since it is among these that the winners are found, -- so it is those who act rightly who carry off the prizes and good things of life.
[tr. Rackham (1934), ch. 8, sec. 9]

And just as in the Olympic Games it is not the noblest and strongest who get the victory crown but the competitors (since it is among these that the ones who win are found), so also among the noble and good aspects of life it is those who act correctly who win the prizes.
[tr. Reeve (1948)]

And as at the Olympic Games it is not the most beautiful or the strongest who are crowned but those who compete (for it is some of these who become victors), so in life it is those who act rightly who become the winners of good and noble things.
[tr. Apostle (1975), ch. 9]

Just as at the Olympic Games it is not the best-looking or the strongest men present that are crowned with wreaths, but the competitors (because it is from them that the winners come), so it is those who act that rightly win the honors and rewards in life.
[tr. Thomson/Tredennick (1976)]

For just as it is not the noblest and strongest who are crowned with the victory wreath at the Olympic Games but rather the competitors (for it is certain of these who win), so also it is those who act correctly who attain the noble and good things in life.
[tr. Bartlett/Collins (2011)]