For many years I have been reading, off and on, the Pelican paperback Zen Flesh, Zen Bones, compiled by Paul Reps (Penquin Books, 1971).
Today I've been pondering Text 38 from The Gateless Gate by Ekai, called Mumon, and transribed by Nyogen Senzaki and Paul Reps. It is entitled An Oak Tree in the Garden:
A monk asked Joshu why Bodhiharma came to China. Joshu said: 'An oak tree in the garden.'
Mumon's Comment: If one sees Joshu's answer clearly, there is no Shakyamuni Buddha before him and no future Buddha after him.
Words cannot describe everything.
The heart's message cannot be delivered in words.
If one receives words literally, he will be lost.
If he tries to explain with words, he will not
attain enlightenment in this life.