Matthew 7:20

ἄραγε : final inference, a very lively and forcible composite particle; again with similar effect in Matthew 17:26. The γε should have its full force as singling out for special attention; “at least from their fruits, if by no other means”. It implies that to know the false prophet is hard. Matthew 7:22 explains why. He has so much to say, and show, for himself: devils cast out, souls saved, spiritual if not physical miracles done. What other or better “fruit” would you have? What in short is the test? Doctrine, good moral life? Is the false prophet necessarily a false teacher or an immoral man? Not necessarily though not unfrequently. But he is always a self-seeking man. The true prophet is Christ-like, i.e., cares supremely for truth, righteousness, humanity; not at all for himself, his pocket, his position, his life. None but such can effectively preach Christ. This repetition of the thought in Matthew 7:16 is not for mere poetical effect, as Carr (Camb. G. T.), following Jebb (Sacred Literature, p. 195), seems to think.