ἐν καιρῷ
From LSJ
ἄμεινον γὰρ ἑαυτῷ φυλάττειν τὴν ἐλευθερίαν τοῦ ἑτέρων ἀφαιρεῖσθαι → for it is better to guard one's own freedom than to deprive another of his
Greek > English (Woodhouse)
early, at the right moment, at the right time, in the nick of time