Ask at the forum if you have an Ancient or Modern Greek query!
Ζῆν οὐκ ἄξιος, ὅτῳ μηδὲ εἷς ἐστι χρηστὸς φίλος → Life is not worth living if you do not have at least one friend.
P. and V. πιθανός, P. ἀναγκαῖος (Thuc. 4, 60).