The Gateless Gate, by Ekai, called Mu-mon, tr. Nyogen Senzaki and Paul Reps [1934], at sacred-texts.com
In a dream Kyozan went to Maitreya's Pure Land. He recognized himself seated in the third seat in the abode of Maitreya. Someone announced: "Today the one who sits in the third seat will preach."
Kyozan arose and, hitting the gavel, said: "The truth of Mahayana teaching is transcendent, above words and thought. Do you understand?"
Mumon's comment: I want to ask you monks: Did he preach or did he not?
When he opens his mouth he is lost. When he seals his mouth he is lost. If he does not open it, if he does not seal it, he is 108,000 miles from truth.