Yogācārabhūmi-śāstra, Volume 34 (65)

Original text: 又于涅槃深心愿乐。速能趣入。心无退转。离诸怖畏。摄受增上意乐适悦。如是行者。于诸圣谛。下忍所摄。能缘所缘平等。平等智生。是名为暖。中忍所摄。能缘所缘平等。平等智生。是名为顶。上忍所摄。能缘所缘平等。平等智生。名谛顺忍。

Explanation: Furthermore, one deeply delights in and aspires to nirvāṇa, swiftly entering into it, with the mind never regressing, free from all fears, embracing intensified mental engagement (adhimātramanaskārabala) with comfort and joy. Such a practitioner, in the cultivation of the four noble truths, is subsumed under the lower grade of acquiescence (kṣānti). When the mind that perceives and the dharma that is perceived are equal, and the wisdom of equality arises, this is called the stage of Heat (ūṣmagata), subsumed under the middle grade of acquiescence. When the mind that perceives and the dharma that is perceived are equal, and the wisdom of equality arises, this is called the Summit (mūrdhan), subsumed under the upper grade of acquiescence. When the mind that perceives and the dharma that are perceived are equal, and the wisdom of equality arises, this is called Acquiescence in Accord with the Truths (Satyānulomikī Kṣānti).

Here, the acquiescence regarding nirvāṇa is divided into three grades: lower, middle, and upper. The lower grade of acquiescence corresponds to the stage of Heat among the four aids to penetration (nirvedha-bhāgīya); the middle grade of acquiescence corresponds to the stage of Summit among the four aids to penetration; the upper grade of acquiescence, also called Acquiescence in Accord with the Truths, corresponds to the stage of Acquiescence among the four aids to penetration. A practitioner at the stage of Heat can already direct the mind toward nirvāṇa, and in cultivating the dharma of nirvāṇa, the mind no longer regresses. Because intensified mental engagement has arisen toward the dharma of nirvāṇa, fears are abandoned, and there is the experiential benefit of merit; hence in all subsequent cultivation there will be no regression—indeed, after eliminating self-view and attaining the first fruit, one will regress even less from the path to nirvāṇa. The experiential benefit of merit at the stage of the four aids to penetration differs greatly from that of the first fruit, and the experiential benefit of merit of the first fruit and the second fruit, and even between the second fruit and the third and fourth fruits, all differ greatly. Therefore, do not misunderstand the experiential benefit of merit; do not mistake the experiential benefit of merit of the four aids to penetration for that of the first or second fruit, thereby committing the great false speech of claiming realization where there is none.