2 John 1:4-11. John is writing to an "elect lady" who has been brought into the faith. He rejoices that some of her children have also been converted. He asks them to follow the "commandment we have had from the beginning, that we love one another." Love, John says, is the keeping of all of God's commandments. John also warns that many deceivers are in the world who will not acknowledge that Jesus Christ came in the flesh. He says to be careful and "look to yourselves, that you may not lose what you have worked for, but may win a full reward." If anyone does not have Christ, he does not have God, and he who has the doctrine of Christ, has both Father and Son. "If anyone comes to you and does not bring this doctrine, do not receive him into the house or give him any greeting; for he who greets him shares his wicked work."

John warns that Christ is essential for salvation - for the "full reward." Without Him, we do not know the Trinity. There will always be people who sound so convincing as they preach about God, but if they do not believe that Jesus Christ is the Son of God who came in the flesh, they are to be avoided lest we put our own salvation in peril. John says "such a one is the deceiver and the antichrist."

It is unlikely we will run into the antichrist (although nowadays i'm not so sure!;), but the devil uses other people to get us to let go of our salvation. It doesn't matter if we are dealing with the antichrist, the devil himself, or just a person who has convinced himself that Christ is not necessary for salvation. All of these people are very dangerous to our wellbeing.