大乘起信論裂網疏 2.89

2.89

此即本覺隨染分別所生不思議用相也。隨所應化，即意輪觀機；現種種色，即身輪示化；現種種聲，即口輪說法。此如太空之含育萬物，明鏡之頓寫千容也。

This is precisely the mark of inconceivable function produced when original awakening accords with defilement and discriminates. "According with those to be transformed" is the mental wheel observing capacities; "manifesting various forms" is the bodily wheel manifesting transformations; "manifesting various sounds" is the vocal wheel teaching the Dharma. This is like the great sky containing and nurturing the ten thousand things, or a bright mirror instantly copying a thousand faces.