Mk 14:50, Jn 2:22, Jn 20:31

Many people followed Jesus to be healed. But after they were healed, they left Jesus. (Lk 17:17-19)

Lk 17:17 And Jesus answering said, Were there not ten cleansed? but where are the nine? 18 There are not found that returned to give glory to God, save this stranger. 19 And he said unto him, Arise, go thy way: thy faith hath made thee whole.

The disciples also followed Jesus through many miracles. But they left him when he was about to die. (Mk 14:50)

Mk 14:50 And they all forsook him, and fled.

Until it is believed that Jesus is the Christ, neither the Old Testament nor the work of Jesus is understood. (Jn 2:22)

Jn 2:22 When therefore he was risen from the dead, his disciples remembered that he had said this unto them; and they believed the scripture, and the word which Jesus had said.

The Bible was written so that we might believe in Jesus as the Christ and be saved. (Jn 20:31)

Jn 20:31 But these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name.