A claim is not evidence because that would be circular reasoning.
Evidence is separate from the claim and backs up the claim so it is not circular.
Let's take some of the "evidence" to the claim that Jesus is the "Son of God" and for many Christians, God himself. He was born of a virgin, thus avoiding the taint of a sin nature. Through the power of God, his father, he performed great miracles including bringing a couple of people back to life. Also, in Matthew, Jesus healed a guy and forgave his sins. Something that the Jews believed only God had the authority to do.
Matthew 9:2 Some men brought to him a paralyzed man, lying on a mat. When
Jesus saw their faith, he said to the man, "Take heart, son; your sins are forgiven." 3At this,
some of the teachers of the law said to themselves, "This fellow is blaspheming!" 4Knowing their thoughts, Jesus said, "Why do you entertain evil thoughts in your hearts? 5Which is easier: to say, 'Your sins are forgiven,' or to say, 'Get up
and walk'? 6But I want you to know that the Son of Man has authority on earth to forgive
sins." So he said to the paralyzed man, "Get up, take your mat and go home." 7Then the man got up and went home. 8When the crowd saw this, they were filled with awe; and they praised God, who had given such authority to man.
Then the big one, He himself rose from the dead. Oh, and I almost forgot, a couple of times God spoke from heaven about Jesus and it was heard by the people present. Oh, and one more, people came out of their graves and walked around Jerusalem for a few days.
I don't know about you, but I would be convinced that God was real and whatever was said about Jesus, I'd believe that too. But now, 2000 years later, do we really believe those things? If we don't and if we question whether or not they really happened, and then if we come to the conclusion that they probably didn't really happen, then where is the "proof" that God is real? And Baha'is don't help in making any of those stories believable, except the supposed virgin birth. So Baha'is themselves destroy the proof Christians offer that God and Jesus are real.