If you ignore its profundity, you can never practice stillness. Like the Great Void, it is Perfect and lacks nothing, nor has any excess. If you discriminate, you will miss its suchness. Cling not to external causes, nor stay in the Void. Differentiation ceases if you can be impartial.
Stillness comes when all disturbances are stopped, clinging to stillness is also a mistake.
This is the Tathagata's Dhyana.