English Macbeth ignment?

I got an english ignment for the play macbeth, where i have to explain a quote. I have to relate it to a real life today and explain how it still is "true" today as well as the deeper meaning of it. The teacher doesnt allow repeated topics and all the good quotes were taken. I chose the quote "The labour we delight in physics pain." said by macbeth. I thought i knew the meaning but i cant expand on it. Any ideas?