1 John 4:2

2 By this you know the Spirit of God: every spirit which confesses that Jesus Christ has come in the flesh is of God,

1 John 4:2 Meaning and Commentary

1 John 4:2

Hereby know ye the Spirit of God
This is a rule by which believers may know whether a man professing to have the Spirit of God, and to be called and sent by him, and whether the, doctrine he preaches, is of him or not:

every spirit that confesseth that Jesus Christ is come in the flesh,
is of God;
or of the Spirit of God; that is, every doctrine which carries this truth in it; or every man that owns, and professes, and publishes this doctrine concerning Christ, is on the side of God and truth; and which contains several articles in it, respecting the person and office of Christ; as that he existed before he came in the flesh, not in the human nature, or as man, or as an angel, but as the Son of God, as a divine person, being truly and properly God; so that this confession takes in his divine sonship, and proper deity, and also his true and real humanity; that the Messiah was incarnate, against the Jews, and was God and man in one person; and that he was really man, and not in appearance only, against the heretics of those times: and it also includes his offices, as that Jesus of Nazareth was the Christ, the Messiah, which the Jews denied, and that he was the anointed prophet, priest, and King; and so is a confession or acknowledgment of all the doctrines of the Gospel, which came by him, as a prophet; and of his satisfaction, sacrifice, and intercession, as a priest; and of all his ordinances and commands as a King; and that he is the only Saviour and Redeemer of men. Now, whoever owns and declares this system of truth, "is of God"; not that everyone that assents unto this, or preaches it, is born of God; a man may believe, and confess all this, as the devils themselves do, and yet be destitute of the grace of God; but the spirit, or doctrine, which contains these things in it, is certainly of God, or comes from him; or whoever brings these truths with him, and preaches them, he is, so far as he does so, on the side of God and truth, and to be regarded.

1 John 4:2 In-Context

1 Beloved, do not believe every spirit, but test the spirits to see whether they are of God; for many false prophets have gone out into the world.
2 By this you know the Spirit of God: every spirit which confesses that Jesus Christ has come in the flesh is of God,
3 and every spirit which does not confess Jesus is not of God. This is the spirit of antichrist, of which you heard that it was coming, and now it is in the world already.
4 Little children, you are of God, and have overcome them; for he who is in you is greater than he who is in the world.
5 They are of the world, therefore what they say is of the world, and the world listens to them.
Revised Standard Version of the Bible, copyright 1952 [2nd edition, 1971] by the Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.