Pearls before swine

Usually in the form of 'cast or casting pearls before swine'. Pearls before swine is a metaphor for items of value or quality offered to those who are not cultured or knowledgeable enough to appreciate them. The source is the New Testament Matthew 7:6 “Give not that which is holy to the dogs, neither cast ye your pearls before swine.” It appears in Tyndale's Bible 1526, but the expression is known in both English and French from the 1400s.