Think not that thy word, and thine alone, must be right.
μή νυν ἓν ἦθος μοῦνον ἐν σαυτῷ φόρει,
ὡς φὴς σύ, κοὐδὲν ἄλλο, τοῦτ᾿ ὀρθῶς ἔχειν.
ὡς φὴς σύ, κοὐδὲν ἄλλο, τοῦτ᾿ ὀρθῶς ἔχειν.
Original text (Ancient Greek)
Notes from Wikiquote
Think not that your word and yours alone must be right. (ed. Moses Hadas, 1965)