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Matthew 7:6 (KJV) - 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.

When thinking about the dogs and swine, we often consider evil sinners that are ravenous toward Christians or non-believers. However, Matthew 7:6 pertains to ANYONE that is unable to appreciate or accept holy and precious gifts of God (knowledge, wisdom, etc.), even if they profess to be a Christian - check their fruit (Luke 6:43-45).

When people cannot appreciate the holy and precious gifts you place before them, they will treat them as worthless (trample them under their feet) and will turn against you (turn again and rend you).