梵網經古迹記 1.90

1.90

述曰：第二地行中有二：總標故，別釋故。此初也。「清淨明達一切善根」者，舉行體也。謂有三種：一、慈與樂為最故，二、捨離染之本故。或有經本具四無量，三、慧證達之原故。「一切功德本」者，釋上善根名義也。

The commentary says: In the practice of the second bhūmi there are two parts: the general presentation and the specific explanation. This is the first. "Pure, clear, and thoroughly penetrating all wholesome roots" presents the essence of practice. That is, there are three kinds: first, loving-kindness is supreme because it bestows happiness; second, equanimity is the basis for leaving defilement behind—or some sūtra recensions possess the four immeasurables; third, wisdom is the source of realizing and penetrating. "The root of all merits" explains the meaning of the name of wholesome roots above.