τὸ λακωνίζειν πολὺ μᾶλλόν ἐστιν φιλοσοφεῖν ἢ φιλογυμναστεῖν → to behave like a Lacedaemonian is much more to love wisdom than to love gymnastics (Plato, Protagoras 342e6)
tui(gen.) PRON REFLEX :: yourself, thyself
tŭī,⁹ gén. de tu.