Matthew 17:20-21

Amplified Bible

²⁰ He answered, “Because of your little faith [your lack of trust and confidence in the power of God]; for I assure you and most solemnly say to you, ^[a]if you have [living] faith the size of a mustard seed, you will say to this mountain, ‘Move from here to there,’ and [if it is God’s will] it will move; and nothing will be impossible for you.^{(A) 21 [b]}[But this kind of demon does not go out except by prayer and fasting.]”