Speak not evil one of another, brethren. He that speaketh evil of his brother, and judgeth his brother, speaketh evil of the law, and judgeth the law: but if thou judge the law, thou art not a doer of the law, but a judge. Speak not evil one of another - Perhaps this exhortation refers to evil speaking, slander, and backbiting in general, the writer having no particular persons in view. It may, however, refer to the contentions among the zealots, and different factions then prevailing among this wretched people, or to their calumnies against those of their brethren who had embraced the Christian faith.
He that speaketh evil of his brother - It was an avowed and very general maxim among the rabbins, that "no one could speak evil of his brother without denying God, and becoming an atheist." They consider detraction as the devil's crime originally: he calumniated God Almighty in the words, "He doth know that in the day in which ye eat of it, your eyes shall be opened, and ye shall be like God, knowing good and evil;" and therefore insinuated that it was through envy God had prohibited the tree of knowledge.
Speaketh evil of the law - The law condemns all evil speaking and detraction. He who is guilty of these, and allows himself in these vices, in effect judges and condemns the law; i.e. he considers it unworthy to be kept, and that it is no sin to break it.
Thou art not a doer of the law, but a judge - Thou rejectest the law of God, and settest up thy own mischievous conduct as a rule of life; or, by allowing this evil speaking and detraction, dost intimate that the law that condemns them is improper, imperfect, or unjust.