Jesus uses them to reveal spiritual truths in ways that only those seeking God will understand. For others, parables might seem like riddles, as seen in Mark 4:12—so "they may be ever seeing but never perceiving." 

Notice: In Mark 4:11, Jesus said, "You are permitted to understand the secret of the Kingdom of God."

Question: Who can understand the secret of the Kingdom of God?Answer: Only disciples.

Question: Why do many, or even the majority of believers, not understand the secret of the Kingdom of God?Answer: Because they have not become true disciples of Jesus. Jesus does not reveal the secret to outsiders, only to insiders.

Points: To understand the secret of the Kingdom of God, you must become an insider—a disciple of Jesus. (V11b) 

Purpose of Concealment: Jesus’ use of parables allows individuals to respond according to their hearts. Those who seek God will dig deeper, while others might dismiss the message.