Where does the term casting pearls before swine come from?

This expression is usually expressed in the negative proverbial form - 'don't cast your pearls before swine', and is found in The Bible, Matthew 7:6, first appearing in English bibles in Tyndale's Bible, 1526:

"Nether caste ye youre pearles before swyne."

The biblical text is generally interpreted to be a warning by Jesus to his followers that they should not offer biblical doctrine to those who were unable to value and appreciate it .