大般涅槃經義記 6.392

6.392

就此品中四門分別：一對問分別，此品答上願說甚深微妙諸行，以此十德契實名深、離相稱妙。

Regarding this chapter, there are four gates of distinction: 1. distinction in response to the question: this chapter answers the preceding vow to explain the profound and subtle practices, for using these ten virtues to accord with reality is called profound, and being free from marks is termed subtle.