Ὡς ὅτ' ἀνὴρ φόρμιγγος ἐπιστάμενος καὶ ἀοιδῆς ῥηϊδίως ἐτάνυσσε νέῳ περὶ κόλλοπι χορδήν. - Homer

Ἐννοσίγαι' οὐκ ἄν με σαόφρονα μυθήσαιο
ἔμμεναι, εἰ δὴ σοί γε βροτῶν ἕνεκα πτολεμίξω
δειλῶν, οἳ φύλλοισιν ἐοικότες ἄλλοτε μέν τε
ζαφλεγέες τελέθουσιν ἀρούρης καρπὸν ἔδοντες,
ἄλλοτε δὲ φθινύθουσιν ἀκήριοι.

For a friend with an understanding heart is worth no less than a brother

. . . But if he is truly

Odysseus, home at last, make no mistake:

we two will know each other, even better — we two have secret signs,

known to us both but hidden from the world.