When Jesus was on earth He sometimes
taught by parables. His disciples didn't
understand some of them, so they asked
Him why and He said to them, "Because
it is given unto you to know the mysteries
of the kingdom of heaven, but to them it is
not given. . . .Therefore speak I to them in
parables: because they seeing see not; and
hearing, they hear not, neither do they
understand. . . .For this peoples's heart is
waxed gross, and their ears are dull of
hearing, and their eyes they have closed;
lest at any time they should see with their
eyes, and hear with their ears, and should
understand with their heart, and should be
converted, and I should heal them."
Matthew 13:11, 13, 15)