Enchiridion · §47
ὅταν εὐτελεῖ σωματοφυλακῇ ἀρεσκόμενος ᾖς, μὴ κομπολάκει περὶ αὐτοῦ, καὶ ἂν ὕδωρ πίνῃς, μὴ λέγε παντοῦ ὅτι ὕδωρ πίνεις. κἂν ἀσκεῖν ποτε θέλῃς πρὸς πόνον, σεαυτῷ καὶ μὴ τοῖς ἔξω· μὴ τοὺς ἀνδριάντας περιαγκαλίζου, ἀλλ᾽ ὅταν σφόδρα διψήσῃς, ψυχρὸν ὕδωρ λαβὼν ἀπόπτυσον καὶ μηδενὶ εἴπῃς.
hotan euthelei sōmatophulakē areskomenos ēs, mē kompollakei peri autou, kai an hudōr pinēs, mē lege pantou hoti hudōr pineis. kan askein pote thelēs pros ponon, seautō kai mē tois exō.
When you have accustomed yourself to a simple, frugal way of living, do not parade it. If you drink only water, do not announce it everywhere. And if you ever wish to train yourself in hardship, do it for yourself alone — not for show. Do not embrace statues in the cold. If you are very thirsty, take a mouthful of cold water, spit it out, and tell no one.
— Enchiridion 47
Source: Greek (Schenkl/Oldfather critical edition tradition) + Long 1877 English translation