The pupils felt sorry to see the old teacher working so hard, but they knew he would not listen to their advice to stop, so they hid away his tools.
That day the master did not eat. The next day he did not eat, nor the next.
"He may be angry because we have hidden his tools," the pupils surmised. "We had better put them back."
The day they did, the teacher worked and ate the same as before.
In the evening he instructed them: "No work, no food."
Zen Principle: Every action around us is triggered by another action or reason. Nothing remains constant, and constant action is the way of nature.