Measure your shadow. Winning didn't make it any longer.

The source

"Measure your shadow. Winning didn't make it any longer." Archidamus said it in Plutarch, Sayings of Spartans, Archidamus son of Agesilaus 1 (218e). Translated from the original Greek by Spartan Surfers.

"εἰ μετρήσαις τὴν σαυτοῦ σκιάν, οὐκ ἂν εὕροις αὐτὴν μείζονα γεγενημένην ἢ πρὶν νικᾶν."

Original Greek, Plutarch, Sayings of Spartans, Archidamus son of Agesilaus 1 (218e). Greek: Bernardakis 1889 (Teubner) via Perseus; Reply to Philip of Macedon after Chaeronea.

Who said it

The Spartans (8th–4th century BC). Laconic sayings from Lycurgus, Leonidas, Dienekes and the mothers of Sparta, recorded by Herodotus and Plutarch.

Questions

Who said "Measure your shadow. Winning didn't make it any longer."?

Archidamus (8th–4th century BC). Source: Plutarch, Sayings of Spartans, Archidamus son of Agesilaus 1 (218e).

What is the original Greek?

εἰ μετρήσαις τὴν σαυτοῦ σκιάν, οὐκ ἂν εὕροις αὐτὴν μείζονα γεγενημένην ἢ πρὶν νικᾶν. Translated from the original Greek by Spartan Surfers.