When Jesus saw their faith, he said to the paralytic, "Son, your sins are forgiven."
Mark 2:1-12
Faith believes that something will occur when, so far, it has not. Personal faith is when you actually do something about that belief. You take action... you commit to that belief.
In this passage we see Jesus teaching in Capernaum to a packed audience. Thick crowds gathered on the news that Jesus had cast a demon out of a man in Capernaum and repeated that all through Galilee, just as Isaiah had prophesized. The town was buzzing.
Now a paraplegic carried by four men could not get in to see Jesus because of the crowd, so they lowered him on his stretcher through the roof. Jesus was impressed by their bold belief and healed him.
Do you think the four men and the paraplegic had good reason to commit themselves to the belief that Jesus would heal? I do. Look, they had all three ways we know something: objective evidence (they saw what others saw), subjective experience (they saw it themselves) and a consistent link with past records, in this case Isaiah's prophecy.
It is no different today. We come to believe something is true when we have all three elements. In 1967, at university in New Zealand, I came to belief because of the historical, eyewitness record of Jesus actions, particularly His resurrection; the "ring of truth" that I felt when I read the Gospel accounts; and the weight of logic that linked the two through Jewish history. This is why I have faith in God through Jesus Christ.
Dean Lewis (2008)