大乘起信論義記 3.185

3.185

此云何示？以一切法本來唯心，實無於念，而有妄心，不覺起念，見諸境界，故說無明。心性不起，即是大智慧光明義故。

"How is this demonstrated? Because all dharmas are originally mind only and are truly devoid of thought, yet there is a deluded mind that in non-enlightenment gives rise to thoughts and perceives objects, it is therefore called avidyā. Because the mind-nature does not arise, this is the meaning of the light of great wisdom."