James 3:6

And the tongue is a fire - In this sense, that it produces a “blaze,” or a great conflagration. It produces a disturbance and an agitation that may be compared with the conflagration often produced by a spark.

A world of iniquity - A little world of evil in itself. This is a very expressive phrase, and is similar to one which we often employ, as when we speak of a town as being a world in miniature. We mean by it that it is an epitome of the world; that all that there is in the world is represented there on a small scale. So when the tongue is spoken of as being “a world of iniquity,” it is meant that all kinds of evil that are in the world are exhibited there in miniature; it seems to concentrate all sorts of iniquity that exist on the earth. And what evil is there which may not be originated or fomented by the tongue? What else is there that might, with so much propriety, be represented as a little world of iniquity? With all the good which it does, who can estimate the amount of evil which it causes? Who can measure the evils which arise from scandal, and slander, and profaneness, and perjury, and falsehood, and blasphemy, and obscenity, and the inculcation of error, by the tongue? Who can gauge the amount of broils, and contentions, and strifes, and wars, and suspicions, and enmities, and alienations among friends and neighbors, which it produces? Who can number the evils produced by the “honeyed” words of the seducer; or by the tongue of the eloquent in the maintenance of error, and the defense of wrong? If all men were dumb, what a portion of the crimes of the world would soon cease! If all men would speak only that which ought to be spoken, what a change would come over the face of human affairs!

So is the tongue among our members, that it defileth the whole body - It stains or pollutes the whole body. It occupies a position and relation so important in respect to every part of our moral frame, that there is no portion which is not affected by it. Of the truth of this, no one can have any doubt. There is nothing else pertaining to us as moral and intellectual beings, which exerts such an influence over ourselves as the tongue. A man of pure conversation is understood and felt to be pure in every respect; but who has any confidence in the virtue of the blasphemer, or the man of obscene lips, or the calumniator and slanderer? We always regard such a man as corrupt to the core.

And setteth on fire the course of nature - The margin is “the wheel of nature.” The Greek word also (τροχός trochos) means “a wheel,” or any thing made for revolving and running. Then it means the course run by a wheel; a circular course or circuit. The word rendered “nature” (γένεσις genesis), means “procreation, birth, nativity;” and therefore the phrase means, literally, the wheel of birth - that is, the wheel which is set in motion at birth, and which runs on through life. - Rob. Lex. sub voce γένεσεως geneseōs. It may be a matter of doubt whether this refers to successive generations, or to the course of individual life. The more literal sense would be that which refers to an individual; but perhaps the apostle meant to speak in a popular sense, and thought of the affairs of the world as they roll on from age to age, as all enkindled by the tongue, keeping the world in a constant blaze of excitement. Whether applied to an individual life, or to the world at large, every one can see the justice of the comparison. One naturally thinks, when this expression is used, of a chariot driven on with so much speed that its wheels by their rapid motion become self-ignited, and the chariot moves on amidst flames.

And it is set on fire of hell - Hell, or Gehenna, is represented as a place where the fires continually burn. See the notes at Matthew 5:22. The idea here is, that that which causes the tongue to do so much evil derives its origin from hell. Nothing could better characterize much of that which the tongues does, than to say that it has its origin in hell, and has the spirit which reigns there. The very spirit of that world of fire and wickedness - a spirit of falsehood, and slander, and blasphemy, and pollution - seems to inspire the tongue. The image which seems to have been before the mind of the apostle was that of a torch which enkindles and burns everything as it goes along - a torch itself lighted at the fires of hell. One of the most striking descriptions of the woes and curses which there may be in hell, would be to portray the sorrows caused on the earth by the tongue.