大乘起信論義記 3.82

3.82

如風依水而動者，喻無明風依心體故有動相，此示無明離於心體不能自現動相也。若水滅乃至無所依止者，此示若境果滅時令心體亦滅者，則無明風無所動故，業等三細則應斷滅。以水不滅風相續者，以境界滅時心體不滅故，無明三細則得長相續。良以無明滅故境界滅，非以境界滅故無明滅。由是義故，境界滅時，無明動心，三細相續。此答初問相應心滅義也。唯風滅乃至非水滅者，以無明盡時，業等動相亦隨之滅，非靜心體而亦滅也。此答後問不相應心滅義。合中次第合前二種心也。

'Like the wind relying on the water to move': this illustrates that the wind of avidyā, relying on the substance of the mind, has marks of movement; this shows that avidyā, apart from the substance of the mind, cannot manifest marks of movement on its own. 'If the water ceases... up to... have nothing on which to rely': this shows that if when the result of perceptual objects ceases it caused the substance of the mind to cease as well, then the wind of avidyā would have nothing to stir, and the three subtle marks such as karma would be severed and cease. 'Because the water does not cease, the wind continues': because when perceptual objects cease the substance of the mind does not cease, the three subtle marks of avidyā are able to continue for a long time. Truly it is because avidyā ceases that perceptual objects cease; it is not because perceptual objects cease that avidyā ceases. By this meaning, when perceptual objects cease, avidyā stirs the mind, and the three subtle marks continue. This answers the first question regarding the meaning of the cessation of the conjoined mind. 'Only because the wind ceases... up to... not that the water ceases': when avidyā is exhausted, the moving marks such as karma also cease accordingly; it is not that the still substance of the mind also ceases. This answers the latter question regarding the meaning of the cessation of the unconjoined mind. In the application, it applies to the aforementioned two kinds of minds in sequence.