俱舍論記 3.40

3.40

「論曰至名曰憂根」者，釋初五句。身有二義。若言六受身，身則是體。若言身受、心受，身即是色聚。色聚名身。此中言身，色聚名身，即諸色根依身起故名為身受，從依為名。餘文易了。問：三定極悅心與樂相應，亦可地獄極不悅心與苦相應。解云：極悅無分別，可與樂相應。極損有分別，非與苦相應。若依大乘，地獄意識亦苦相應。

Regarding "The treatise says: ... is named the faculty of grief": this explains the first five lines. "Body" has two meanings. If one speaks of the six bodies of sensation, "body" is the real entity. If one speaks of bodily sensation and mental sensation, "body" is the aggregation of form (rūpa). An aggregation of form is named "body." Here, "body" means the aggregation of form; that is, because the material faculties arise based on the body, it is called bodily sensation, taking its name from its basis. The rest of the text is easy to understand.

Question: The third dhyāna is extremely delightful to the mind and associates with pleasure; likewise, hell is extremely unpleasant to the mind and should associate with pain.
Explanation: Extreme delight is without conceptual discrimination, so it can associate with pleasure. Extreme harm has conceptual discrimination, so it does not associate with pain. If based on the Mahāyāna, the mental consciousness in hell also associates with pain.