Do not throw pearls to swine.
More Spanish Proverbs:
A fool, if he holds his tongue, passes for wise.Spanish
The tiger that has once tasted blood is never sated with the taste of it.
Spanish
A turn of the key is better than the conscience of a friar.
Spanish
Guests always have nice backs.
Spanish
It is very savoury to eat scot free.
Spanish
The greatest victory is a bloodless victory.
Spanish