The word here used for deluding (παραλογιζόμενοι) is found nowhere else in the New Testament, excepting in one passage in the Epistle to the Colossians (ii. 4), in which St. Paul warns them against allowing any one to "delude them with persuasiveness of speech." But the word is fairly common both in ordinary Greek and in the Septuagint. Its meaning is to mislead with fallacious reasoning, and the substantive (παραλογισμός) is the Aristotelian term for a fallacy. The word does not necessarily imply that the fallacious reasoning is known to be fallacious by those who employ it. To express that we should rather have the word which is used in 2 Peter i. 16 to characterize "cunningly devised fables" (σεσοφισμένοι μῦθοι). Here we are to understand that the victims of the delusion do not, although they might, see the worthlessness of the reasons upon which their self-contentment is based. It is precisely in this that the danger of their position lies. Self-deceit is the most subtle and fatal deceit. The mere knowledge of the law derived from their attentive listening to it does but increase their evil case, if they do not practise it. "To him that knoweth to do good, and doeth it not, to him it is sin" (iv. 17). The Jews have a saying that the man who hears without practising is like a husbandman who ploughs and sows, but never reaps. Such an illustration, being taken from natural phenomena, would be quite in harmony with the manner of St. James; but he enforces his meaning by employing a far more striking illustration. He who is a hearer and not a doer "is like unto a man beholding his natural face in a mirror." Almost all the words in this sentence are worthy of separate attention.