成唯識論述記 7.159

7.159

述曰：其彼憂根，五十七說：隨順行相，深求解脫，故不同惡作，憂根許為三無漏根故，如《對法》第十。

The Commentary states: Regarding that faculty of sorrow, fascicle fifty-seven states that by conforming in its mental configuration, it deeply seeks liberation; therefore it is not like remorse. The faculty of sorrow is accepted as belonging to the three uncontaminated faculties, as in fascicle ten of the Abhidharma-samuccaya.