俱舍論疏 27.110

27.110

論「云何此名至得邊際名」，釋增至究竟。由此定先順一切，後入第四定，名一切地隨順。就第四定中，從下至上名增至究竟。由斯二義得邊際名。

The Śāstra states: "Why is this called up to obtains the name of 'summit'," explaining the increase to the ultimate. Because this samādhi first accords with all, and subsequently enters the fourth dhyāna, it is called according with all levels. Within the fourth dhyāna itself, proceeding from lower to upper is called increasing to the ultimate. Due to these two meanings, it obtains the name of 'summit'.