"And the disciples came, and said unto him, Why speakest thou unto them in parables? And he answered and said unto them, Because it is given unto you to know the mysteries of the kingdom of heaven, but to them it is not given. For whosoever hath, to him shall be given, and he shall have more abundance. But whosoever hath not, from him shall be taken even that which he hath." - Matthew 13:10-12
Recommended reading:
The Bible
Is the Bible Infallible?