When he became emancipated the sixth patriach received from the fifth patriach the bowl and robe given from the Buddha to his successors, generation after generation.

A monk named E-myo out of envy pursued the patriach to take this great treasure away from him. The sixth patriach placed the bowl and robe on a stone in the road and told E-myo: “These objects just symbolize the faith. There is no use fighting over them. If you desire to take them, take them now.”

When E-myo went to move the bowl and robe they were as heavy as mountains. He could not budge them. Trembling for shame he said: “I came wanting the teaching, not the material treasures. Please teach me.”
The sixth patriach said: “When you do not think good and when you do not think not-good, what is your true self?”

At these words E-myo was illumined. Perspiration broke out all over his body. He cried and bowed, saying: “You have given me the secret words and meanings. Is there yet a deeper part of the teaching?”
The sixth patriach replied: “What I have told you is no secret at all. When you realize your true self the secret belongs to you.”

E-myo said: “I was under the fifth patriach for many years but could not realize my true self until now. Through your teaching I find the source. A person drinks water and knows himself whether it is cold or warm. May I call you my teacher?”

The sixth patriach replied: “We studied together under the fifth patriach. Call him your teacher, but just treasure what you have attained.”
-----------
http://www.inspirationalstories.com/do-not-think-good-do-not-think-not-good/