ἐκδεκτέον
From LSJ
ψυχῆς πείρατα ἰὼν οὐκ ἂν ἐξεύροιο πᾶσαν ἐπιπορευόμενος ὁδόν· οὕτω βαθὺν λόγον ἔχει → one would never discover the limits of soul, should one traverse every road—so deep a measure does it possess
English (LSJ)
A one must admit, include, Ath.5.189d, Dam.Pr.437.
Greek (Liddell-Scott)
ἐκδεκτέον: ῥηματ. ἐπί. παραδεκτέον, Ἀθήν. 189D.