大般涅槃經義記 8.153

8.153

六中，前五虛妄不真，生滅流轉，非是常、樂、我、淨之法，不能究竟為佛真種，今此不論。第六一門體真常、樂、我、淨之法，能為佛種，今名中道，與經中說生、死二法是如來藏其言相似。「如是中道能破生、死，故名中道」釋為中義。中道即是因緣實性，是實性中無因緣相故破生死。生死之有著邊故起，故破生死名為中道。「以是中道名佛性」者，結中為性。以是中道能破生死，成佛義故，得名佛性。

Among the six, the first five are false and unreal, flowing in arising and ceasing; they are not dharmas of permanence, bliss, self, and purity, and cannot ultimately serve as the true seed of a buddha, so they are not discussed here. The sixth single approach, being in essence real dharmas of permanence, bliss, self, and purity, can serve as the buddha-seed; here it is called the middle way, and its phrasing is similar to when the sūtra states that the two dharmas of birth and death are the tathāgatagarbha. "Such a middle way can destroy birth and death, hence it is called the middle way" explains the meaning of being the middle. The middle way is the real nature of dependent origination; because within this real nature there are no marks of dependent origination, it destroys birth and death. The existence of birth and death arises because of attachment to extremes; therefore destroying birth and death is called the middle way. "Because of this middle way it is called the buddha-nature" concludes the middle as the nature. Because this middle way can destroy birth and death and accomplish the meaning of buddhahood, it receives the name buddha-nature.