1 John 4:3 3And every spirit which does not confess Jesus is not from God; And this [spirit] is the antichrist, which you heard because he is coming, and now is already in the world.
We can further identify false prophets and teachers by what they say. John gets right to the heart of the central confession of Christians: Jesus is the primary and clearest revelation of the Almighty God, Creator of the universe. In this verse, spirit has the implication that the ones who do not confess an orthodox confession of Christ are human, or at least, they are human instruments of spirits who have deceived them into accepting false doctrine. Today, there are multiple wrong interpretations of Jesus and his coming in the flesh as both human and divine.
Any distortion of Christology is not from God, meaning it is from the evil one. The divinity of Jesus is not disputed. Any questions about this crucial point indicate someone is an antichrist. The Greek of this word simply indicates someone “against Christ.” The test or determining factor of heresy is what someone says about Jesus. John saw the danger already arising in his time. He seems to indicate in this verse with the singular verb that a specific person will be the antichrist. It is also possible to interpret the idea as a more general reference to either Satan, who opposes Christ, or any person or demonic force that wars against true believers or who teaches false doctrine. All these entities can be fitted into the same general category of deceit and heresy.
When we begin to speculate beyond the revelation in the Bible, we will find ourselves on shaky theological ground. Diminishing any person of the Trinity distorts theology and will lead to a deterioration of ethics. One does not need to be orthodox to live holy outwardly, but one must exalt Jesus Christ as Lord to be holy inwardly. Outward holiness without the inward holiness degenerates into legalism and works righteousness.
Obedience is the outcrop of what God’s grace does within us and our response to God’s love. It is working out our salvation with fear and worship, resulting in strengthened and more focused faith. Just as in John’s day, people today oppose Christ through outright antagonism and rejection, and distort true doctrine through heretical teaching. Genuine followers of Jesus must be aware and know the truth of the gospel in order to see these false messages and not be deceived by them.