Hekiganroku - Case 65: A Non-Buddhist Questions Buddha [1]

A non-Buddhist asked Buddha,
  "I do not ask about words, I do not ask about no-words."
Buddha remained still. The non-Buddhist praised him and said, 
  "The great benevolence and great mercy of the World-Honored One have opened
   the clouds of my delusion and enabled me to enter the Way."
After the non-Buddhist took his leave, Ananda asked Buddha,
  "What did the non-Buddhist realize so that he said you had enabled him
   to enter the Way?"
Buddha said, 
  "He is like a fine horse that runs even at the shadow of a whip."

[1]: Cf. case 32 in the Mumonkan.