大般涅槃經疏 19.4

19.4

The beginning of the fascicle is the second [major section], praising the power of the sūtra to eliminate evil. "Evil" refers to icchantikas, the four grave offenses, and the five heinous sins—it can extinguish them all. An older interpretation holds: King Ajātaśatru's heinous sin was real, and the power of the sūtra was able to extinguish it. It is not that this meaning is absent, yet the Guhyakādhipatinirdeśa Sūtra states: "King Ajātaśatru employed skillful means to manifest the way to extinguish heinous sins." By analogy, one knows that Devadatta's breaking of the Saṃgha was certainly not a real breaking, just as Sunakṣatra's manifesting as an icchantika was not truly an icchantika, and Nanda's committing a grave offense was also not a real offense. The majestic power of this sūtra can remove grave evils, causing those who actually commit them to definitively take refuge; this precisely reveals that pure conduct renders the impure pure. Emperor Wu of Liang did not understand this, claiming that this passage of text was not part of the sūtra's proper sequence and calling it a "guest chapter". If one grasps the meaning of rendering the impure pure, it is precisely pure conduct and is not called a "guest chapter".