Luzu asked Nanquan, “People don’t recognize the wish-fulfilling gem. I picked it up myself in the Tathagata treasury. What is this treasury?”
  Nanquan said, “It’s me engaged in conversation with you like this.”
  “How about when there’s no conversation?”
  “That’s it, too.”
  “What is the jewel?”
  “Reverend Luzu!”
  “Yes?”
  “Go on, you don’t understand my words.”

Case 93, The Book of Serenity