Not thinking about anything is zen. Once you know this, walking, standing, sitting, or lying down, everything you do is zen. To know that the mind is empty is to see the buddha.... Using the mind to reality is delusion. Not using the mind to look for reality is awareness. Freeing oneself from words is liberation.
Bodhidharma (2009). “The Zen Teaching of Bodhidharma”, p.49, Macmillan