"Difficulties strengthen the mind, as labor does the body."

Seneca  (ca. 4 BCE-65 ACE)

"I knew there was an old axe down in the cellar; that is all I knew."

Lizzie Andrew Borden (1860-1927)

"A man is a worker.  If he is not that he is nothing."

Joseph Conrad (1857-1924)

"If you want creative workers, give them enough time to play."

John Cleese (1939-present)

"Light is the task where many share the toil."

Homer (Scholars are unsure.  Probably  8th century BCE)

"Work consists of whatever a body is obliged to do.  Play consists of whatever a body is not obliged to do."

Mark Twain (1835-1910)

"If there was nothing wrong in the world there wouldn't be anything for us to do."

George Bernard Shaw (1856-1950)

"Life grants nothing to us mortals without hard work."
Horace (65-8 BCE)

"The end of labor is to gain leisure."

Aristotle (384-322 BCE)