大乘起信論義記 2.267

2.267

[The text states:] "The third is named manifesting consciousness, meaning that it is able to manifest all sense-objects, just as a bright mirror manifests visible forms; the manifesting consciousness is also like this: following the five dusts, as they confront it, it immediately manifests them without prior or posterior, because at all times it arises spontaneously and is always in front."