wat baten kaars en bril als de uil niet zien en wil

Etymology
Literally, “what use are [the] candle and [the pair of] glasses if the owl doesn't want to see”.

Proverb

 * 1) If somebody doesn't want to learn or cooperate, there's no use in helping him or her to do so

Usage notes
The second en, before wil, is the negation particle.