There was once a great Chinese man of Zen named Chao-chou. When Chao-chou was fifty years old, his master, Nan-ch'uan, died. After three years of mourning, Chao-chou, at age sixty, set out on a twenty-one-year-long pilgrimage that took him throughout China. At the age of eighty, the extraordinary Zen master Chao-chou settled in a temple called Kuan-yin-yuan, where he guided monks and lay persons in the Dharma until his death at one hundred and twenty years of age. One day a monk in training came to Chao-chou's temple and inquired, "What is the most solid, most unbreakable thing in this world?"

Chao-chou replied, "If you feel like insulting me, go right ahead and insult me as you please. If your initial insults do not suffice, pour on still more abuse. if you want to spit on me, go right ahead and spit to your heart's content. If spitting isn't enough, go and dip up some muddy water and slosh that on me as well."