大乘起信論廣釋卷第三．四．五 4.1

4.1

First, it reveals the reason for the conditioned arising of avidyā; later, it reveals the marks of the defiled mind in conditioned arising. This is the first. This […] the prior statement that although there is a defiled mind, it is ever constant and unchanging. The words "although defiled, there is a defiled mind that is constantly unchanging" constitute the defilement of active and objective thought; therefore, thought-defilement is used to explain its unchanging nature. First, because its own nature is constantly luminous and pure, it does not change, constituting the defilement of active thought. Second, because its own nature cannot be grasped, it does not change, constituting the defilement of objective thought. Thus the new translation states: "Although there is a defiled mind, it is constantly luminous and pure, without alteration. Furthermore, because its original nature has no differentiated clarity, even though it pervades all cognitive objects, it has no variation." Although this text is brief, its meaning is complete; therefore, having no thought is called unchanging.