In 4:1 John says, “Beloved, do not believe every spirit, but prove the spirits whether they are out of God, because many false prophets have gone out into the world.” This verse tells us clearly to prove, discern, the spirits. We should not think that a particular teaching simply comes from the teaching one himself. No, every teaching, whether right or wrong, comes by a spirit. As there are different teachings, there are also different spirits. Hence, we need to test the spirits to see whether they have their source in God, whether they are out of God. In verse 2 John says that every spirit which confesses that Jesus Christ has come in the flesh is out of God. But in verse 3 he says that every spirit which does not confess Jesus is not out of God, for this is the spirit of the antichrist.
The expressions “every spirit” in verses 2 and 3 and “the spirits” in verse 1 refer either to the spirit of the prophets (1 Cor. 14:32) motivated by the Spirit of truth, or to the spirit of the false prophets actuated by the spirit of deception. Every prophet, whether a real prophet or a false one, has his own spirit. When a real prophet speaks, with his spirit there is the motivating of the Spirit of God. But when a false prophet speaks, his spirit is activated by another spirit, by a spirit of deception. Hence, there is the need to discern the spirits by proving them to see whether they are out of God.
We should not think that teaching is merely a matter of the mind and the mouth. With every kind of speaking, every kind of teaching, the spirit of the speaker either is motivated by the Spirit of God or is actuated by a spirit of deception. This means that the speaking of any kind of doctrine always comes from a certain kind of spirit, either from the spirit of a genuine prophet motivated by the Spirit of God or from the spirit of a false prophet actuated by an evil spirit.
According to 4:2, the discernment of spirits is based upon whether or not a spirit confesses that Jesus Christ has come in the flesh. Because the spirit of a genuine prophet is motivated by the Holy Spirit of truth, this spirit will confess the divine conception of Jesus and affirm that He was born as the Son of God. Every such spirit is surely out of God.
The word “flesh” in 4:2 is very important. As human beings, we were all born of flesh to be flesh (John 3:6a). Thus every human being is flesh. To confess Jesus Christ coming in the flesh is to confess that He was divinely conceived to be born as the Son of God (Luke 1:31-35). This is marvelous! Christ is God incarnate to become a man through holy conception. He did not have a human father, for He was conceived of the Holy Spirit. His conception is holy because it was carried out by the Holy Spirit. Although He was conceived of the Holy Spirit, this conception took place in the womb of a virgin. Therefore, He, the very God, became a man in the flesh. Contrary to the false teaching of the Docetists, His body was not a phantasm. Rather, He had a real body, a physical body that was solid in its substance. He was conceived of the Holy Spirit; He became flesh and was born of the virgin Mary. Because He was conceived of the Spirit to be born in the flesh, the Spirit would never deny that He has come in the flesh through divine conception.
Anyone who denies that Jesus Christ has come in the flesh denies that He was conceived of the Holy Spirit. Furthermore, anyone who rejects Jesus Christ coming in the flesh rejects His humanity and His human living. Such a one also rejects Christ’s redemption. If Christ had not become a genuine man, He could not have had human blood to shed for the redemption of human beings. If He had not become flesh through the conception of the Holy Spirit in the womb of the virgin Mary, He never could have been our Substitute to be crucified to bear our judgment before God. Therefore, to deny that Jesus Christ has come in the flesh is to deny His holy conception, His incarnation, His birth, His humanity, His human living, and also His redemption. The New Testament makes it emphatically clear that Christ’s redemption was accomplished in His human body and by the shedding of His blood.
Anyone who rejects Christ’s incarnation and thereby rejects His redemption also denies Christ’s resurrection. If Christ had never passed through death, it would not have been possible for Him to enter into resurrection.
Denying that Jesus Christ has come in the flesh is a great heresy. This heretical teaching makes it impossible to have the enjoyment of the Trinity. According to the revelation of the Trinity in the New Testament, the Son came in the flesh with the Father and in the name of the Father. The Son was crucified, and in resurrection He became the life-giving Spirit. Therefore, we have the Spirit as the reality of the Son with the Father. This includes incarnation, human living, redemption by the shedding of human blood, death in a human body, burial, and resurrection. All these are components, constituents, of our enjoyment of the Triune God. If anyone denies Christ’s incarnation, that one denies Christ’s holy birth, humanity, human living, redemption through crucifixion, and resurrection. This utterly annuls the enjoyment of the genuine Trinity. Knowing the seriousness of this matter, John included 4:1-6 in his Epistle as a warning to the believers concerning the need to prove the spirits.