Pearls before swine
Items of quality offered to those who aren't cultured enough to appreciate them.
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.
It had existed in the language for some time before that, in various forms. It may have migrated from France, as it is found in a Middle French text from 1402 as 'jeter des perles aux pourceaux'. It is also found in Middle English, in Langland's Piers Plowman, which is of uncertain date, but appeared around the same time:
Nolite mittere, Man, margerie perlis Among hogges...
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.
See also: the List of Proverbs.