This is one of the more important questions Jesus asked his disciples. Here is the text:
And Jesus went out, and his disciples, into the towns of Caesarea Philippi: and by the way he asked his disciples, saying unto them, Whom do men say that I am?
29 And he saith unto them, But whom say ye that I am? And Peter answereth and saith unto him, Thou art the Christ.
30 And he charged them that they should tell no man of him.
We can see here that the Christ, Christos and the Son of man are synonymous.
The devil knew Jesus was the Son of God, Mt. 4. Devil spirits knew he was the Son of God as well, Mt. 8:29, Mk. 3:11. Martha believed it as well, Jn. 11:26.
Yet, today most of Christianity believes something entirely different. The reason it is so critical to know and believe who Jesus Christ was and is, is because it is foundational. The apostle Paul laid the foundation for the Christian Church:
1 Cor 3:10-15
As an expert builder using the grace that God gave me, I laid the foundation, and someone else is building on it. But each person must be careful how he builds on it. 11 After all, no one can lay any other foundation than the one that is already laid, and that is Jesus the Messiah. 12 Whether a person builds on this foundation with gold, silver, expensive stones, wood, hay, or straw, 13 the workmanship of each person will become evident, for the day of judgment will show what it is, because it will be revealed with fire, and the fire will test the quality of each person’s action. 14 If what a person has built on the foundation survives, he will receive a reward. 15 If his work is burned up, he will suffer loss. However, he himself will be saved, but it will be like going through fire.
If you believe that Jesus Christ is someone other than who he is your work that you are building is not “in Christ,” and consequently you will suffer the loss of rewards because of it. You will still be saved but you may be a little singed!
Some men have told me, “I would rather have 1700 years of church history on my side to support what I believe.” Really? There will be no pointing fingers at the Judgment seat of Christ, sorry. You will be all alone and solely accountable. All that matters is believing what the Word of God says, not history.
“God is not a man, that He should lie,
Nor a son of man, that He should repent;
Who do you believe Jesus is?