Pearls before the swine

What does "I will not cast pearls before the swine" mean?

It means that something precious should not be wasted on those who are incapable of appreciating its value.

An example might be that one wouldn't use a subtle and sophisticated piece of reasoning on someone who couldn't understand it.

Its origins are Biblical (I think) and are something like 'Cast not your pearls before swine'.

DFG