Ζῆν οὐκ ἄξιος, ὅτῳ μηδὲ εἷς ἐστι χρηστὸς φίλος → Life is not worth living if you do not have at least one friend.
adj.
Allegorical: P. ἐν ὑπονοίαις πεποιημένος (Plat., Rep. 378D).