大乘起信論別記 1.40

1.40

問：此本覺性，為當通為染淨因性，為當但是諸淨法性？若言但是淨法因者，何故經云「如來藏者是善不善因」乃至廣說。若通作染淨者，何故唯說具足性功德，不說具足性染患耶？答：此理通與染淨作性，是故唯說具性功德。是義云何？以理離淨性故，能隨緣作諸染法；又離染性故，能隨緣作諸淨法。以能作染淨法故，通為染淨性；由離染淨性故，唯是性功德。何以得離染淨性？乃成諸功德。取著染淨性，皆是妄想故。

Question: Is this nature of innate enlightenment universally the causal nature for both defilement and purity, or is it only the nature of all pure dharmas? If one says it is only the cause of pure dharmas, why does the sūtra say that "the tathāgatagarbha is the cause of both wholesome and unwholesome [dharmas]," and so on at length? If it universally constitutes defilement and purity, why does [the treatise] only speak of being endowed with nature qualities, and not speak of being endowed with defiled afflictions of the nature? Answer: This principle universally serves as the nature for both defilement and purity, and for this reason it only speaks of being endowed with nature qualities. What does this mean? Because the principle is free from a pure nature, it can accord with conditions to produce all defiled dharmas; and because it is free from a defiled nature, it can accord with conditions to produce all pure dharmas. Because it can produce defiled and pure dharmas, it universally serves as the defiled and pure nature; because it is free from defiled and pure natures, it is purely nature qualities. Why is it that being free from defiled and pure natures constitutes all qualities? Because grasping at a defiled or pure nature is entirely conceptual proliferation.