If We Don't Confess God's One Christ, Jesus, God Says We Don't Know God

2 John 1:7-11
⁷  For many deceivers are entered into the world, who confess not that Jesus Christ is come in the flesh. This is a deceiver and an antichrist.
⁸  Look to yourselves, that we lose not those things which we have wrought, but that we receive a full reward.
⁹  Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God. He that abideth in the doctrine of Christ, he hath both the Father and the Son.
¹⁰ If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed: 

¹¹  For he that biddeth him God speed is partaker of his evil deeds.  

Who is this Jesus Christ, about whom the Bible's Old and New Testaments both are so adamant, saying that we must be born again of His Spirit and Word?  

How can I repent and receive His salvation?

What are the consequences if I choose to neglect God's plan of salvation?