Matthew 17:19-23

Then came the disciples to Jesus apart, and said, Why could not we cast him out? And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you. Howbeit this kind goeth not out but by prayer and fasting.

And while they abode in Galilee, Jesus said unto them, The Son of man shall be betrayed into the hands of men: and they shall kill him, and the third day he shall be raised again. And they were exceeding sorry.