Zazen is a deep unoccupiedness – not doing anything outwardly, not doing anything inwardly. It is not even meditation because when you meditate you are making some sort of effort, you are trying to do something: chanting a mantra, remembering God, or even remembering yourself.

But these efforts create ripples, these efforts create vibrations and your sitting becomes corrupted. Then your sitting is not innocent. Zazen means: sit, and just sit, nothing else.  -Osho