Related:

• The gem cannot be polished without friction, nor man perfected without trials.
• Better a diamond with a flaw than a pebble without. -- Confucius, Analec
• No great discovery was ever made without a bold guess. -- Sir Isaac Newto
• Prosperity is not without many fears and distaste
  and adversity is not without comforts and hopes. -- Francis Bacon (1561-1626) -- Of Adversity...
• Learning without thought is labor lost. CONFUCIUS
• Learning without thought is labor lost; thought without learning is perilous. -- Confuciu
• Study without though is useless. Thought without learning is dangerous. -- Confucius, The Analec
• Man who meows ate pussy! -- Confucius Say