Albert Barnes Commentary James 4:12

"One [only] is the lawgiver and judge, [even] he who is able to save and to destroy: but who art thou that judgest thy neighbor?" — James 4:12 (ASV)

There is one lawgiver. There is only one who has a right to give law. The reference here is undoubtedly to the Lord Jesus Christ, the great Legislator of the church.

This, too, is a most important and vital principle, though one that has been most imperfectly understood and acted on.

The tendency everywhere has been to enact other laws than those appointed by Christ—the laws of synods and councils—and to claim that Christians are bound to observe them and should be punished if they do not.

But it is a fundamental principle in Christianity that no laws are binding on the conscience except those which Christ has ordained. All attempts to make other laws pertaining to religion binding on the conscience are a usurpation of his prerogatives.

The church is safe while it adheres to this as a settled principle; it is not safe when it submits to any legislation in religious matters as binding the conscience.

Who is able to save and to destroy. . The idea here would seem to be that he is able to save those whom you condemn, and to destroy you who pronounce a judgment on them.

Or, in general, it may mean that he is entrusted with all power and is abundantly able to administer his government: to restrain where it is necessary to restrain, to save where it is proper to save, and to punish where it is just to punish.

The whole matter pertaining to judgment, therefore, may be safely left in his hands. As he is abundantly qualified for it, we should not usurp his prerogatives.

Who art thou that judgest another? Who are you, a weak, frail, and erring mortal, yourself accountable to that Judge, that you should interfere and pronounce judgment on another, especially when he is doing only what that Judge permits him to do? See the comments on Romans 14:4 for this sentiment explained at length. See also the comments on Romans 2:1 and Matthew 7:1.

There is nothing more decidedly condemned in the Scriptures than the habit of pronouncing a judgment on the motives and conduct of others. There is nothing in which we are more liable to err, or to indulge in wrong feelings; and there is nothing which God claims more for himself as his peculiar prerogative.