I John 4: 1 – 3: Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world. 2 Hereby know ye the Spirit of God: Every spirit that confesses that Jesus Christ is come in the flesh is of God: 3 And every spirit that confesses not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.
Believing that Jesus is the Son of God Who came in the flesh is the dividing line of humanity. Like the proverbial line in the sand, we can’t get past it. Jesus told Thomas “I am the Way, the Truth, and the Life: no man comes unto the Father, but by Me.” John 14:6
Mankind has built theories and creeds, religions and dogmas, but in the end the way to God is found only through the sacrifice of Jesus Christ. All else will fail.