Polishing A Tile

A Zen Koan.

Nanyue visited his friend, Mazu, at his home. When he arrived, Mazu stood up. 

Nazyue said, what have you been doing these days? 

Mazu said, I have just been sitting.

Nanyue said, what is your intention in just sitting? 

Mazu said, I intend to become a Buddha. 

Then Nanyue picked up a tile and started polishing it on a stone near Mazus hut. 

Mazu said, master, what are you doing? 

Nanyue said, polishing a tile. 

— But why are you polishing the tile? 

— I am trying to make it a mirror. 

— How can you polish a tile and make a mirror? 

Nanyue replied — how can you do zazen and become a Buddha? 

Mazu said — then how can I do it? 

Nanyue said — When driving a cart, if it stops moving, do you whip the cart or the ox?