Matthew 17:19-20 Then came the disciples to Jesus apart, and said, Why could not we cast him out?

AKJV⁽ⁱ⁾ ¹⁹ Then came the disciples to Jesus apart, and said, Why could not we cast him out? ²⁰ And Jesus said to them, Because of your unbelief: for truly I say to you, If you have faith as a grain of mustard seed, you shall say to this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible to you.