Enchiridion · §46

μηδαμοῦ σαυτὸν εἴπῃς φιλόσοφον μηδὲ λάλει τὸ πολὺ ἐν τοῖς ἰδιώταις περὶ τῶν θεωρημάτων, ἀλλὰ ποίει τὸ ἀπὸ τῶν θεωρημάτων· οἷον ἐν συμποσίῳ μὴ λέγε πῶς δεῖ ἐσθίειν, ἀλλ᾽ ἔσθιε ὡς δεῖ. μέμνησο γὰρ ὅτι Σωκράτης καὶ οὕτω πάντῃ τὴν ἐπίδειξιν ἀπεβάλετο ὥσθ᾽ οἱ βουλόμενοι παρ᾽ αὐτοῦ φιλοσόφοις συστηθῆναι ἥκοντες ὑπ᾽ αὐτοῦ ἀπῆγοντο· οὕτως ἠνείχετο τοῦ ἀγνοεῖσθαι.

mēdamou sauton eipēs philosophon mēde lale to polu en tois idiōtais peri tōn theōrēmatōn, alla poiei to apo tōn theōrēmatōn; hoion en sumposiō mē lege pōs dei esthiein, all' esthie hōs dei.

Never introduce yourself as a philosopher, and do not lecture laypeople at length about philosophical principles. At a dinner, for example, show how one ought to eat — by eating that way yourself — rather than by pronouncing rules about it. Remember that Socrates so thoroughly avoided all ostentation that when people came to him wanting introductions to philosophers, he simply sent them off to others. That is how tolerant he was of being overlooked.

— Enchiridion 46

Source: Greek (Schenkl/Oldfather critical edition tradition) + Long 1877 English translation