Your cup is full

Nan-in, a Japanese master during the Meiji era (1868-1912), received a university professor who came to inquire about Zen. Nan-in served tea. He poured until his visitor’s cup was full, and then continued to pour. The professor watched the tea overflow until he no longer could restrain himself. “It is overfull. No more will go in!” “Like this cup,” Nan-in said, “you are full of your own opinions and speculations. How can I show you Zen unless you first empty your cup?"