Matthew 17:19-21

Darby Translation

¹⁹ Then the disciples, coming to Jesus apart, said [to him], Why were not *we* able to cast him out?

²⁰ And he says to them, Because of your unbelief; for verily I say unto you, If ye have faith as a grain of mustard [seed], ye shall say to this mountain, Be transported hence there, and it shall transport itself; and nothing shall be impossible to you.

²¹ But this kind does not go out but by prayer and fasting.