In the Tang Dynasty, there was a Guanyin Temple on the Southern Mountain of Hengshan. The temple was stately and solemn, with incense smoke curling all around.
One day, the eminent Chan Monk Huai Rang strolled into the temple hall and saw Monk Ma Zu sitting calmly on a rush cushion, with his palms together and eyes closed in deep meditation.
Knowing that Ma Zu aspired to become a Buddha, Huai Rang smiled to himself. He picked up a brick at random, squatted down, and began to grind it noisily.
Disturbed by the noise, Ma Zu opened his eyes and saw his master grinding a brick. He asked, "Master, what are you doing?"
Huai Rang replied, "I am grinding this brick to make a mirror."
Ma Zu laughed and said, "Can a brick be ground into a mirror?"
"If a brick cannot be ground into a mirror," replied Huai Rang, "then can you become a Buddha by sitting in deep meditation?"
Ma Zu was displeased and asked, "What do you mean?"
Huai Rang explained, "Consider an ox pulling a cart that does not move. Should you whip the ox or push the cart?"
Ma Zu hesitated and could not answer.
At this moment, Huai Rang said to him seriously, "You learn meditation to become a Buddha. However, becoming a Buddha relies on the wisdom and comprehension of the mind, not on sitting.
"A Buddha has no fixed form; therefore, the mind should not fixate on any single object. To seek Buddhism through seated meditation is to throttle the Buddha. If you obstinately cling to external forms, you will never comprehend the true Buddhist doctrine."