Hereby know ye the Spirit of God - We know that the man who teaches that Jesus Christ is the promised Messiah, and that he is come in the flesh, is of God - is inspired by the Divine Spirit; for no man can call Jesus Lord but by the Holy Ghost.
Hereby - Greek, “By this;” that is, by the test which is immediately specified.
Know ye the Spirit of God - You may discern who are actuated by the Spirit of God.
Every spirit - Everyone professing to be under the influence of the Spirit of God. The apostle uses the word “spirit” here with reference to the person who made the claim, on the supposition that everyone professing to be a religious teacher was animated by some spirit or foreign influence, good or bad. If the Spirit of God influenced them, they would confess that Jesus Christ had come in the flesh; if some other spirit, the spirit of error and deceit, they would deny this.
That confesseth - That is, that makes a proper acknowledgment of this; that inculcates this doctrine, and that gives it a due place and prominence in his instructions. It cannot be supposed that a mere statement of this in words would show that they were of God in the sense that they were true Christians; but the sense is, that if this constituted one of the doctrines which they held and taught, it would show that they were advocates of truth, and not apostles of error. If they did not do this, 1 John 4:3, it would be decisive in regard to their character and claims.
That Jesus Christ is come in the flesh - Benson and some others propose to render this, “That Jesus, who came in the flesh, is the Christ.” But this is liable to serious objections.
(1)it is not the obvious interpretation.
(2)it is unusual to say that Jesus “had come in the flesh,” though the expression “the Son of God has come in the flesh,” or “God was manifested in the flesh,” would be in accordance with the usage of the New Testament.
(3)this would not, probably, meet the real point in the case. The thing denied does not appear to have been that Jesus was the Messiah, for their pretending to be Christian teachers at all implied that they admitted this; but that the Son of God was “really a man,” or that he actually assumed human nature in permanent union with the divine. The point of the remark made by the apostle is, that the acknowledgment was to be that Christ assumed human nature; that he was really a man as he appeared to be: or that there was a real incarnation, in opposition to the opinion that he came in appearance only, or that he merely seemed to be a man, and to suffer and die. That this opinion was held by many, see the Introduction, Section III. 2. It is quite probable that the apostle here refers to such sentiments as those which were held by the “Docetae;” and that he meant to teach that it was indispensable to proper evidence that anyone came from God, that he should maintain that Jesus was truly a man, or that there was a real incarnation of the Son of God. John always regarded this as a very important point, and often refers to it, John 19:34-35; John 20:25-27; 1 John 5:6. It is as important to be held now as it was then, for the fact that there was a real incarnation is essential to all just views of the atonement. If he was not truly a man, if he did not literally shed his blood on the cross, of course all that was done was in appearance only, and the whole system of redemption as revealed was merely a splendid illusion. There is little danger that this opinion will be held now, for those who depart from the doctrine laid down in the New Testament in regard to the person and work of Christ, are more disposed to embrace the opinion that he was a mere man; but still it is important that the truth that he was truly incarnate should be held up constantly before the mind, for in no other way can we obtain just views of the atonement.
Is of God - This does not necessarily mean that everyone who confessed this was personally a true Christian, for it is clear that a doctrine might be acknowledged to be true, and yet that the heart might not be changed; nor does it mean that the acknowledgment of this truth was all which it was essential to be believed in order that one might be recognised as a Christian; but it means that it was essential that this truth should be admitted by everyone who truly came from God. They who taught this held a truth which he had revealed, and which was essential to be held; and they thus showed that they did not belong to those to whom the name “antichrist” could be properly given. Still, whether they held this doctrine in such a sense, and in such connection with other doctrines, as to show that they were sincere Christians, was quite another question, for it is plain that a man may hold and teach the true doctrines of religion, and yet have no evidence that he is a child of God.