Matthew 13:10-15

10The disciples came to him and asked, “Why do you speak to the people in parables?” 11He replied, “Because the knowledge of the secrets of the kingdom of heaven has been given to you, but not to them. 12Whoever has will be given more, and they will have an abundance. Whoever does not have, even what they have will be taken from them.

13This is why I speak to them in parables: “Though seeing, they do not see; though hearing, they do not hear or understand.

14In them is fulfilled the prophecy of Isaiah: “ ‘You will be ever hearing but never understanding; you will be ever seeing but never perceiving.

15For this people’s heart has become calloused; they hardly hear with their ears, and they have closed their eyes. Otherwise they might see with their eyes, hear with their ears, understand with their hearts and turn, and I would heal them.’ Isaiah 6:9,10 (see Septuagint)