In Attic, and in part also in Homer, ἄρα marks an inference (
quently, so then, therefore, it seems, after all, of course, etc.). Thus, εἶπεν αὐτῷ ὅτι βασιλεὺς οὐ μαχεῖται δέκα ἡμερῶν· Κῦρος δ' εἶπεν· οὐκ ἄρα ἔτι μαχεῖται, εἰ ἐν ταύταις οὐ μαχεῖται ταῖς ἡμέραις the seer said to him that the king would not fight within ten days. And Cyrus answered: “Well then if he does not fight within that time he will not fight at all”
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].