When the Master [Tung-shan] first set out on pilgrimage, he met an old woman carrying water. The Master asked for some water to drink.
The old woman said, "I will not stop you from drinking, but I have a question I must first ask. Tell me, how dirty is the water?"
"The water is not dirty at all," said the Master.
"Go away and don't contaminate my water buckets," replied the old woman.
Who makes dirty? Who makes clean?