Matthew 13:11-14

And He replied to them, To you it has been given to know the secrets and mysteries of the kingdom of heaven, but to them it has not been given. For whoever has [spiritual knowledge], to him will more be given and he will be furnished richly so that he will have abundance; but from him who has not, even what he has will be taken away. This is the reason that I speak to them in parables: because having the power of seeing, they do not see; and having the power of hearing, they do not hear, nor do they grasp and understand. In them indeed is the process of fulfillment of the prophecy of Isaiah, which says: You shall indeed hear and hear but never grasp and understand; and you shall indeed look and look but never see and perceive.