ἆρα,
interrog. particle, implying anxiety or impatience, "quite rare and only in Luke and Paul, therefore a literary word" (Bl., §77, 2).
1. (num igitur) expecting a neg. reply, Lk 18:8; ἆρά γε, Ac 8:30.
2. (ergone) in apodosis, expecting an affirm. reply, Ga 2:17 (Bl., §77, 2; Lft., Ga., in l.; MM, s.v.).†