The following earth-shaking chapter in the Bible presents a challenge to any thinking person. On the one hand, it declares, for the first time anywhere, that God IS love. Nothing could be more universal! On the other hand, it makes a statement that has given rise to the worst intolerance among Christians!
"Every spirit that confesseth that Jesus Christ is come in the flesh is of God: And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist." What gives? Here is my take:
John wrote this letter to faithful Christians a few decades after the resurrection. I doubt he envisioned his letter would be distributed universally for all time in the Bible! He was addressing a world where Jesus' life, crucifixion, and resurrection had been in the news for a while. It was a very hot topic. Many had been slaughtered for professing to follow the Christ message. Then there were those who denied that Jesus ever existed, perhaps the intellectual type who did not feel the spirit, and simply pooh-poohed the whole thing. "Show me the DNA samples, or I will not believe!" This was the type that John warned against. They might seem fine, educated, highly regarded in society, but watch out! For anybody to be so spiritually insensitive, so unwilling to feel this momentous event - this is the spirit of anti-christ.
Another point - in order to be the disciple closest to Jesus, John could not have had a personal relationship with him, but rather understood that Jesus did not think of himself so much as a person but as Principle, God in operation. When Jesus declared that if those who believed in him would have eternal life, he could not have been talking about his person - it had to be obeying the principles he taught and lived. And so the quote above must be understood with emphasis on the Principle that Christ Jesus taught and lived - the very laws of the universe. Denial of all this is the spirit of anti-christ.
The intolerance of non-believers by certain Christian sects stems from a mistaken sense that professing stuff is all-important, along with having a personal relationship with Jesus, both of which are entirely off course, actually a denial of the life and teaching of Christ Jesus.
It is intriguing to hear that there is no historical record of Jesus outside the Bible, and yet there has been no one life and teaching that has had greater impact on humanity. "It is the spirit that quickeneth; the flesh profiteth nothing."