When they reached the crowd, a man approached and knelt down before Him. “Lord,” he said, “have mercy on my son, because he has seizures and suffers severely. He often falls into the fire and often into the water. I brought him to Your disciples, but they couldn’t heal him.”
Jesus replied, “You unbelieving and rebellious generation! How long will I be with you? How long must I put up with you? Bring him here to Me.” Then Jesus rebuked the demon, and it came out of him, and from that moment the boy was healed.
Then the disciples approached Jesus privately and said, “Why couldn’t we drive it out?”
“Because of your little faith,” He told them. “For I assure you: If you have faith the size of a mustard seed, you will tell this mountain, ‘Move from here to there,’ and it will move. Nothing will be impossible for you. [However, this kind does not come out except by prayer and fasting.]”
(Matthew 17:14-21 Holman Christian Standard Bible ®©)
Faith is really simple. It is not difficult for a child to believe our lies about Spring Goddess (easter) bunnies or Santa Claus or a tooth fairy. If we teach them instead that Jesus heals and that He raises the dead, that He is a King Who is worthy to be worshiped and obeyed, the simple but powerful faith that they attach to those truths can real-ize them very powerfully in their lives.