1 John 4:15
 Whoever confesses that Jesus is the Son of God, God abides in him, and he in God. (ESV)
The reality of Jesus as a historical person on this earth is undisputed. Our western calendar is based upon the fact of Jesus' historic birth. Christianity is based upon those who follow Jesus. Many may dispute whether or not there is a God. Many dispute whether or not Jesus himself was, and is, God, but history confirms the reality of Jesus' existence.
John makes clear that if we claim to abide in God, and have God abide in us, there is a critical requirement for us. We must confess that Jesus is the Son of God. It seems that many of the people we meet will confess anything but that Jesus is the Son of God. Every belief system outside of Christianity diminishes the deity of Jesus Christ.
The title Son of God is a title of being equal with God the Father. When you consider Jesus' claims you come to realize that he did not allow for other religions to also be right. He claimed to be the one and only way of salvation. There was salvation in no other name. There are those who want to believe that they do not have to confess that Jesus is the only Son of God. They want to believe that in some way all religions are equal. The late John Lennon typifies that view in the following statement:
"I believe in God, but not as one thing, not as an old man in the sky. I believe that what people call God is something in all of us. I believe that what Jesus and Mohammed and Buddha and all the rest said was right. It's just that the translations have gone wrong.
- John Lennon
I love John Lennon's creativity in song writing. But he is dead wrong about Jesus. If you want to have an abiding relationship with God it is essential that you confess that Jesus Christ is the Son of God. There are no exceptions. He did not leave us any. I leave you with these challenging words from the Apostle Paul:
 so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth,  and every tongue confess that Jesus Christ is Lord, to the glory of God the Father. (ESV)