釋氏要覽 1.175

1.175

Whenever a monastery opens three gates, or even when there is only one gate, why is it also called the 'Three Gates'? The Buddhabhūmi-śāstra states: 'The great palace has the three gates of liberation as its points of entrance.' The great palace is a metaphor for the nirvāṇa of emptiness of phenomena. The three gates of liberation refer to the gate of emptiness, the gate of signlessness, and the gate of wishlessness. Present-day monasteries are inhabited by people who uphold precepts, cultivate the Path, and seek to attain nirvāṇa; therefore, they enter through the Three Gates.