Passage 6.10.2
ἐθεάσατο ὁ Δημύλος τὸ ὑπὸ τοῦ παιδὸς ποιούμενον καὶ ἐπὶ τούτῳ πυκτεύσοντα ἐς Ὀλυμπίαν αὐτὸν ἀνήγαγεν. ἔνθα δὴ ὁ Γλαῦκος ἅτε οὐκ ἐμπείρως ἔχων τῆς μάχης ἐτιτρώσκετο ὑπὸ τῶν ἀνταγωνιζομένων, καὶ ἡνίκα πρὸς τὸν λειπόμενον ἐξ αὐτῶν ἐπύκτευεν, ἀπαγορεύειν ὑπὸ πλήθους τῶν τραυμάτων ἐνομίζετο· καί οἱ τὸν πατέρα βοῆσαί φασιν "ὦ παῖ τὴν ἀπʼ ἀρότρου" . οὕτω γε δὴ βιαιοτέραν ἐς τὸν ἀνταγωνιζόμενον ἐνεγκὼν τὴν πληγὴν αὐτίκα εἶχε τὴν νίκην.
Demylos observed what the boy was doing, and, seeing this, brought him to Olympia to compete in boxing. There, indeed, Glaukos, being inexperienced in fighting, was severely injured by his opponents; and when he was boxing against the last remaining competitor, it seemed to everyone that he would give in from the multitude of his wounds. At that moment, they say, his father cried out to him, "My son, the blow from the plow!" Thus moved, he immediately dealt his opponent a heavier blow and secured the victory.