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

Wesley⁽ⁱ⁾ ¹⁹ Then the disciples coming to Jesus apart said, Why could not we cast him out? ²⁰ And Jesus said to them, Because of your unbelief. For verily I say to you, If ye have faith as a grain of mustardseed, ye shall say to this mountain, Remove hence to yonder place, and it shall remove, and nothing shall be impossible to you.