Where does the expression “casting pearls before swine” come from and What does it mean?

“Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you.”

That is the sixth verse of the seventh chapter of Matthew.

Of the passage John Wyclif wrote in 1380: “Dus (Thus) comaundeth crist bat men schullen not yeve (give) holy bingis to hondis (hounds) & putten precious perles to hoggis.”

That is, grandmother, don’t bequeath the most revered among your treasured antiques to a daughter or daughter-in-law who cares only for modernistic decor, and, granddad, no matter how generous your instincts, you are merely casting pearls before swine in giving your six-year-old grandson a set of ivory chessmen at Christmas, rather than lead Indians.