孔子: Choose a job that you desire and love most, and you will never feel that you work even for one day in your life.

《論語‧雍也篇》：「知之者不如好之者，好之者不如樂之者」

This Confucius quote is somewhat not quite accurately translated in English. But the point is clear. At least this is the closest quote I think is being referred to by the English translation.