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Phrase(s): cast (one’s) pearls before swine
Fig. to waste something good on someone who doesn’t care about it. (From a biblical quotation.) • To sing for them is to cast pearls before swine. • To serve them French cuisine is like casting one’s pearls before swine.
McGrawhill's American Idioms And Phrasal Verbs
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Give something of value to someone who won't appreciate it, as in The old professor felt that lecturing on Dante to unruly undergraduates would be casting pearls before swine. This term comes from the New Testament (Matthew 7:6), appearing in Tyndale's translation (1526). It was repeated often by writers from Shakespeare to Dickens and remains current.
American Heritage Idioms