Or, better yet, here:
The Master was entering an army encampment to attend a dinner when he saw one of the officers at the gate. He pointed to a bare wooden gatepost and said, "A common mortal or a sage?" The officer had no reply. The Master struck the gatepost and said, "Even if you had managed a reply, it would still just be a wooden post!" With that he entered the camp.
Someone asked, "what is the true nature of mind?" The Master replied, "officially even a needle cannot enter; unofficially you can drive a horse and cart through."