Matthew 17:14-21
14 And when the disciples came to Jesus privately, they said, "Why could we not cast it out?"
15 And he said to them, "Because of your little faith. For truly, I say to you, if you have faith like a grain of mustard seed, you will say to this mountain, 'Move from here to there,' and it will move; and nothing will be impossible for you.
16 But this kind does not go out except by prayer and fasting."
17 While they were still in Galilee, Jesus said to them, "The Son of Man is about to be delivered into the hands of men,
18 and they will kill him, and on the third day he will be raised." And they were greatly distressed.
19 When they came to Capernaum, those who collected two-drachma coins came to Peter and said, "Does your teacher not pay the two-drachma tax?"
20 He said, "Yes." And when he came into the house, Jesus spoke first, saying to him, "What do you think, Simon? From whom do the kings of the earth collect toll or tax, from their own children, or from others?"
21 "From others," he said. Jesus said to him, "Then the children are exempt.
22 However, so that we may not cause them offense, go to the sea, and cast a hook, and take the first fish that comes up; and when you open its mouth, you will find a four-drachma coin; take that and give it to them for you and me."