Cross reference
Mark 9:28
28 When he had come into the house, his disciples asked him privately, "Why couldn't we cast it out?"
Mark 7:17
17 When he had entered into a house away from the multitude, his disciples asked him about the parable.
Matthew 13:10
10 The disciples came, and said to him, "Why do you speak to them in parables?"
Matthew 13:36
36 Then Jesus sent the multitudes away, and went into the house. His disciples came to him, saying, "Explain to us the parable of the darnel of the field."
Matthew 15:15
15 Peter answered him, "Explain the parable to us."
Matthew 17:19-20
19 Then the disciples came to Jesus privately, and said, "Why weren't we able to cast it out?"
20 He said to them, "Because of your unbelief. For most assuredly I tell you, if you have faith as a grain of mustard seed, you will tell this mountain, 'Move from here to there,' and it will move; and nothing will be impossible for you.
Mark 4:10
10 When he was alone, those who were around him with the twelve asked him about the parables.
Mark 4:34
34 Without a parable he didn't speak to them; but privately to his own disciples he explained all things.