Matthew 17:14-20

¹⁴And when they were come to the multitude, there came to him a man, kneeling to him, ¹⁵and saying, Lord, have mercy on my son: for he is epileptic, and suffereth grievously; for ofttimes he falleth into the fire, and ofttimes into the water. ¹⁶And I brought him to thy disciples, and they could not cure him. ¹⁷And Jesus answered and said, O faithless and perverse generation, how long shall I be with you? how long shall I bear with you? bring him hither to me. ¹⁸And Jesus rebuked him; and the demon went out of him: and the boy was cured from that hour.¹⁹Then came the disciples to Jesus apart, and said, Why could not we cast it out? ²⁰And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.