Quote:
	
	
		| it didn't stop him nicking and adapting for Aragorn the "All that glisters is not gold" line from Merchant of Venice. | 
	
  Now that is just a common, widespread proverb, so you can't say Tolkien quoted Shakespeare when he used it! (and he turned it around: "all that is gold does not glitter"!)
And apropos the witches in Macbeth: in "On Fairy-stories"  Tolkien wrote that he thought them tolerable when just 
reading the play, but on stage he didn't approve of them at all!  (And he 
did write about Shakespeare "Which I disliked cordially" in letter 163)
 I am quite sure he did 
not use that phrase! I'm fairly certain I would have noticed and not forgotten about it. (If I think of all the "proverbs" and wise sayings I collected...  

  Have a look at the quotable quotes,  ninlaith, you can see that there are people here who do remember lots of sentences literally!)