八識規矩補註 2.46

2.46

When this consciousness reaches the stage of the Buddha-fruit, it is transformed into a supreme undefiled pure essence, termed the immaculate consciousness; when it arises simultaneously with the corresponding great round mirror wisdom, it universally illuminates the perfect, radiant Dharma realm of the ten directions. The sūtra states: "The Tathāgata's immaculate consciousness / is the pure undefiled realm, / liberated from all obstacles, / associated with the round mirror wisdom." Universally distinguishing the four wisdoms: equality wisdom and marvelous observation wisdom each have three grades: inferior on the path of seeing, middling on the path of cultivation, and supreme at the ultimate; therefore they are transformed in the causal stage. The great round mirror wisdom and the duty-fulfillment wisdom are each only of the supreme grade; therefore they are transformed in the fruit. Thus the verse states: "The sixth and seventh consciousnesses are transformed in the causal stage; / the first five and the eighth are perfected in the fruit."