Here and in Matthew 13:10-17 Jesus is explaining to His disciples the reason why He spoke in Parables. To the Believer, the Spiritual truths revealed in the Parables only deepened and fostered their relationship with their Savior…but to those who had already rejected Him, they lacked divine enlightenment…and no amount of explanation would ever enable them to understand the concepts. Paul wrote about this in I Corinthians 1:26-29 showing that no one can “know” God by worldly wisdom & learning. Nor is His election contingent on the worldly qualities of wisdom, power, pedigree, or purity, that is until God’s grace washes & sanctifies the person in Christ…removing the veil from supernatural revelation.