ὑπαρκτέον
From LSJ
λύπης ἰατρός ἐστιν ὁ χρηστὸς φίλος → a true friend is grief's physician, a worthy friend is a physician to your pain
English (LSJ)
A one must begin with, τι Pl.R.467c; τῶν ἴσων ὑ. αὐτῷ he must render equal initial services (to others), Aristid.Or.23(42).29.
Greek (Liddell-Scott)
ὑπαρκτέον: ῥηματ. ἐπίθ., πρέπει τις νὰ ἀρχίσῃ, τι Πλάτ. Πολ. 467C.