The Gateless Gate, by Ekai, called Mu-mon, tr. Nyogen Senzaki and Paul Reps , at sacred-texts.com
Shogen asked: "Why does the enlightened man not stand on his feet and explain himself?" And he also said: "It is not necessary for speech to come from the tongue."
Mumon's comment: Shogen spoke plainly enough, but how many will understand? If anyone comprehends, he should come to my place and test out my big stick. Why, look here, to test real gold you must see it through fire.