The great master Yunmen, thirty-ninth generation from the Buddha, said to a group in a lecture, “All people have a light, but when they look at it they do not see it, so it is obscure. What is everyone’s light?” No one replied, so the master himself said in their behalf, “The communal hall, the Buddha shrine, the kitchen pantry, the mountain gate.”
Now when the great master says that everyone has a light, he does not say it is to appear later on, nor that it existed in the past, nor that it becomes apparent to a view from the side: he is stating that everyone has a light. This is exactly what is meant in the overall sense by the light of great wisdom: it should be heard and retained, enjoyed and applied, in the skin, flesh, bones, and marrow.
The light is everyone: Shakyamuni and Maitreya are its servants. What is not more in Buddhas or less in ordinary beings is this spiritual light, so it is existent in all, it is the whole earth as a single mass of fire.
By Zen Master Ejo in Minding Mind: A Course in Basic Meditation, translated by Thomas Cleary, page 59.