1 John 4:3

and every spirit that confesseth not Jesus is not of God: and this is the spirit of the antichrist, whereof ye have heard that it cometh; and it is in the world already.

That confesseth not Jesus ... The person of the Son of God is the center of all true religion. No matter how attractive a system may be, no matter how skillfully it may be advocated by personable and attractive personnel, no matter how imposing are the names of "authorities" associated with it, no matter how popular it may become - any and every religion or philosophy that is not anchored in both the eternal deity of Jesus Christ and in his historical humanity is false, having its origin in Satan, not in God.

The New Catholic Bible translated this verse: "Every spirit that severs Jesus is not of God, but of Antichrist," admitting in the footnote, however, that this is not the best rendition of the Greek.[14] It is included here, however, as valid comment on the implications of the passage. The heresy of the age was that of making a "severance" between Jesus as a man, and the Christ. The church historian Socrates affirmed that this was the original reading of the letter,[15] but this is rejected by current scholarship.

The spirit of the antichrist ... There is no need whatever to capitalize Antichrist. As Macknight said, "From this, as well as from 1 John 2:18, it appears that Antichrist is not any particular person, nor any particular succession of persons in the church."[16] It is thus clearly a mistake to identify this with Paul's "man of sin" in 2 Thessalonians 2, as so many have done. Both, however, share in the fact of originating in the devil, not in Christ, and also in this, that the spirit of both was already working in the world at the time the apostles wrote.

[14] New Catholic Bible (New York: Catholic Book Publishing Company, 1949), New Testament, p. 317.

[15] David Smith, op. cit., p. 189.

[16] James Macknight, Macknight on the Epistles, 1John (Grand Rapids, Michigan: Baker Book House, reprint, 1969), p. 88.