Based on Mark 9:14–29.

One time, Jesus observed His disciples in the midst of a large crowd and some teachers of the law arguing with them. So Jesus asked, “What is this argument about?”

A man explained to Jesus, “I brought my son to receive help because he has a bad spirit in him that causes him to have violent fits, and he cannot talk. But your disciples couldn’t heal him.”

“How long has he been like this?” asked Jesus.

“Ever since he was a child” answered the father. “Have pity on us and help us, if you can!”

Jesus replied to the father, “You said, ‘If you can.’ Believe! Everything is possible for the person who has faith.”

The father cried out, “I do have faith, but not enough. Help me have more!”

Jesus then ordered the bad spirit to leave the boy and to never return to him again.