Matthew 17:14-20 CSB
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 terribly. 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 perverse 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 truly I tell 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.”
CSB: Christian Standard Bible