大般涅槃經義記 4.64

4.64

第三明凡見性之中初明難見，凡夫說我不當性故，「若有凡夫能善說」下還明依經故能見性。前中迦葉先問起發，問由前生，如來向說佛性甚深，唯佛能知，二乘不及，故今問之。非聖凡夫有眾生性皆說有我，是則凡夫亦能知性，云何佛說唯佛能知，二乘不及？下佛答之，明凡說我虛妄不真，故不知性。於中初先辨妄異真，明凡不見。「今日如來所說我」下簡真異妄，彰性難見。

In the third part, explaining ordinary beings' seeing of the nature: first, it explains that it is difficult to see, because when ordinary beings speak of a self, it does not correspond to the nature; from 'if there is an ordinary being who is able to speak well' onward, it conversely explains that by relying on the sūtra they are therefore able to see the nature. In the former part, Kāśyapa first asks to initiate [the dialogue]; the question arises from what preceded: the Tathāgata just stated that the buddha-nature is extremely profound, only a buddha can know it, and the two vehicles cannot reach it, hence he asks now. Ordinary beings who are not noble ones possess the sentient-being nature and all speak of having a self; if so, ordinary beings can also know the nature—how then does the Buddha say that only a buddha can know it and the two vehicles cannot reach it? Below, the Buddha answers him, explaining that ordinary beings' speaking of a self is false and unreal, and thus they do not know the nature. Within this, it first distinguishes the false from the true, explaining that ordinary beings do not see. From 'the self that the Tathāgata speaks of today' onward, it distinguishes the true from the false, manifesting that the nature is difficult to see.