大般涅槃經義記 6.20

6.20

上來明空，下約辨觀。先觀內空，於中初問、次辯、後結。辯中義三，文別有四。言義三者：一觀內中無彼妄計眾生壽命常樂我淨、二於此空中無其外物、三於此空中無佛法僧及與佛性。以此相空未及實故，始從內空乃至無始例有此三，但於空中所無異耳。

The above clarifies emptiness; below, the contemplation is explained in relation to it. First is contemplating internal emptiness, wherein there is first a question, next an explanation, and finally a conclusion. In the explanation there are three meanings, and in the text there are distinctly four parts. As for the three meanings: first, contemplating that within the internal there are no falsely conceptualized sentient beings, life-spans, permanence, bliss, self, or purity; second, within this emptiness there are no external objects; third, within this emptiness there are no Buddha, Dharma, Saṅgha, or buddha-nature. Because this emptiness of marks does not yet reach the real, starting from internal emptiness down to beginningless emptiness all three are present by analogy, differing only in what is absent within the emptiness.