Note 31 — Chapter XXII · MENON.
Reading edition
To use the phrase of Plato himself in the Euthyphron, p. 11 A, the οὐσία must be known before the πάθη are sought — κινδυνεύεις, ὦ Εὐθύφρον, ἐρωτώμενος τὸ ὅσιον, ὅ, τί ποτ’ ἐστι, τὴν μὲν οὐσίαν μοι αὐτοῦ οὐ βούλεσθαι δηλῶσαι, πάθος δέ τι περὶ αὐτοῦ λέγειν, ὅ, τι πέπονθε τοῦτο τὸ ὅσιον, φιλεῖσθαι ὑπὸ πάντων θεῶν· ὅ τι δὲ ὄν, οὔπω εἶπες.
Compare Lachês, p. 190 B and Gorgias, pp. 448 E, 462 C.