Darby(i)
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.