Matthew 13:10
And the disciples said to Him, Why do You speak to them in parables?
Mark 4:10
And when He was alone, they who were about Him, with the Twelve, asked Him concerning the parable.
Mark 4:33-34
And with many such parables He spoke the Word to them, as they were able to hear it.
Treasury of Scripture Knowledge
Summary
And the disciples came, and said unto him, Why speakest thou unto them in parables?