I brought him to your disciples, but they could not heal him."
"O unbelieving and perverse generation," Jesus replied, "how long shall I stay with you? How long shall I put up with you? Bring the boy here to me."
Jesus rebuked the demon, and it came out of the boy, and he was healed from that moment.
Then the disciples came to Jesus in private and asked, "Why couldn't we drive it out?"
He replied, "Because you have so little faith. I tell you the truth, if you have faith1 as small as a mustard seed,2 you can say to this mountain, 'Move from here to there' and it will move.3 Nothing will be impossible for you. "
References for Matthew 17:20
When they came together in Galilee, he said to them, "The Son of Man4 is going to be betrayed into the hands of men.
References for Matthew 17:22
They will kill him,5 and on the third day6 he will be raised to life."7 And the disciples were filled with grief.
References for Matthew 17:23
After Jesus and his disciples arrived in Capernaum, the collectors of the two-drachma tax8 came to Peter and asked, "Doesn't your teacher pay the temple tax ?"
References for Matthew 17:24
"Yes, he does," he replied. When Peter came into the house, Jesus was the first to speak. "What do you think, Simon?" he asked. "From whom do the kings of the earth collect duty and taxes9--from their own sons or from others?"
References for Matthew 17:25
"From others," Peter answered. "Then the sons are exempt," Jesus said to him.
"But so that we may not offend10 them, go to the lake and throw out your line. Take the first fish you catch; open its mouth and you will find a four-drachma coin. Take it and give it to them for my tax and yours."
References for Matthew 17:27