Matthew 13:10
Afterwards his disciples came to him, and said: "Why do you speak to them in parables?"
Mark 4:10
Afterwards, when he was alone, his followers and the Twelve asked him about his parables;
Mark 4:33-34
With many such parables Jesus used to speak to the people of his Message, as far as they were able to receive it;
Treasury of Scripture Knowledge
Summary
And the disciples came, and said unto him, Why speakest thou unto them in parables?