釋禪波羅蜜次第法門 5.164

5.164

第一、釋四禪名者，禪名支林，四禪攬四支成定，於第四心中證得，故名四禪，猶是無覺無觀三昧聖默然攝，亦名不動定。《地持經》說：「名捨俱禪。」此定發時，體無苦樂，與微妙捨受俱發。此定與捨根相應，故名捨俱禪。

First, explaining the name of the fourth dhyāna: dhyāna is named as a grove of factors; the fourth dhyāna gathers four factors to form absorption, and is realized in the fourth mind, hence it is called the fourth dhyāna. It is still subsumed under the noble silence of the samādhi without vitarka and without vicāra, and is also called the unshakeable absorption. The *Bodhisattvabhūmi-sūtra* says: 'It is named the dhyāna associated with equanimity.' When this absorption manifests, its essence is without suffering or bliss, and it arises together with exquisite equanimity feeling. This absorption is associated with the equanimity faculty, hence it is called the dhyāna associated with equanimity.