ἀγρυπνητέον
From LSJ
Ἐχθροῖς ἀπιστῶν οὔποτ' ἂν πάθοις βλάβην → Minus dolebis, quo hostibus credes minus → Dem Feind misstrauend bleibst von Schaden du verschont
English (LSJ)
A one must watch, Eust 168.16.
Greek (Liddell-Scott)
ἀγρυπνητέον: ῥηματ. ἐπίθ., πρέπει νὰ ἀγρυπνῇ τις, Εὐστ. Ἰλ. Β. 25.
Spanish (DGE)
hay que vigilar, mantenerse alerta Eust.168.16.