αὐτὸν κέκρουκας τὸν βατῆρα τοῦ λόγου → you have struck the very threshold of the argument, you have struck the most important and chiefmost point
ἑήνδᾰνε: Ἐπ. γ΄ ἑν. ἐνεργ. παρατ. τοῦ ἁνδάνω.
see ἁνδάνω.