Osho - Empty your Cup

The Japanese Master Nan-In gave audience to a professor of philosophy.

Serving Tea, Nan-in filled his visitors cup, and kept pouring.

The professor watched the overflow until he could restrain himself no longer.

"Stop! The cup is overfull, no more will go in."

Nan-in said, "Like this cup, you are full of your own opinions and speculations. How can I show you zen unless you first empty your cup?"

Source: Osho - A Bird on the wing.