Mark 9:28

And he saith unto them, Are ye so without understanding also? Do ye not perceive, that whatsoever thing from without entereth into the man, it cannot defile him;

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.

And the disciples came, and said unto him, Why speakest thou unto them in parables?

And when he was alone, they that were about him with the twelve asked of him the parable.

But without a parable spake he not unto them: and when they were alone, he expounded all things to his disciples.

Then answered Peter and said unto him, Declare unto us this parable.

Then Jesus sent the multitude away, and went into the house: and his disciples came unto him, saying, Declare unto us the parable of the tares of the field.