Commentary on the Pitāputrasamāgama Sūtra (134)

What are the Three Gates of Liberation

All dharmas are entirely empty and quiescent; this is called the Gate of Liberation through Emptiness. Yet emptiness itself has no characteristic of emptiness; the dharma of emptiness inherently lacks the mark of emptiness. It is merely a nominal concept, without any form. Emptiness has no form; it possesses not even the form of emptiness. This is called the Gate of Liberation through Signlessness. If all signs are absent, then what aspirations or desires remain? What hopes or wishes could there be? Since all dharmas are empty, what else could one hope for? With no wishes or aspirations left, this is called the Gate of Liberation through Wishlessness. When these three dharmas are practiced together with emptiness, the mind is liberated. This is called the Three Gates of Liberation.

Emptiness, signlessness, and wishlessness—where “wish” refers to aspiration, desired outcomes, or vows undertaken—arise because everything is ultimately devoid of substance. Whatever one grasps at is empty; even attaining Buddhahood is ultimately empty. As stated in the Diamond Sutra, the fruit of Buddhahood is ungraspable. If even the fruit of Buddhahood cannot be attained, what else could one possibly obtain? No matter what we believe we have gained, upon thorough analysis and examination, it becomes clear that nothing has been obtained at all. There is fundamentally no obtainer, let alone any obtainable dharma.