σπαρτέον
From LSJ
ἄλογον δὴ τὸ μήτε μάχης ἄρξασθαι μήτε τοὺς φίλους φυλάξαι, ἐὰν ὑπό γε τῶν βαρβάρων ἀδικῆσθε → It is irrational neither to begin battle nor to guard the friends, if you are ever wronged by the foreigners
English (LSJ)
(σπείρω)
A one must sow, Gp.2.13.2.
Greek (Liddell-Scott)
σπαρτέον: ῥηματ. ἐπίθ. τοῦ σπείρω, πρέπει να σπείρῃ τις, Κλήμ. Ἀλ. 188.