The Mirror of Zen

In all of the sutras expounded by the Buddha, he first
draws distinctions between various kinds of Dharmas,
and then only later explains the principle of emptiness.
The Zen meditation tradition handed down from the
Patriarchs teaches, however, that when all traces of
thinking are cut off, the principle of emptiness appears
clearly, of itself, as the very origin of mind.

Gatha

Contort your body as you may, and yet still
You cannot bend your arm backward at the elbow.

Commentary

The Buddha is a teacher for all generations, so his teachinng on
the principle of emptiness is as complete and meticulous as is
possible to communicate. On the other hand, Patriarchs awaken
others to liberation directly, so their teachings are primarily focused
on attaining sudden enlightenment. The term traces refers
to the Patriarch's words, and thinking refers to the thinking of the
student.