大般涅槃經義記 4.129

4.129

上來滅罪，第二令人發心之中先嘆經勝，初喻、後合；「何以」下釋，令人發心，故得為勝。言「入眾生諸毛孔」者，凡夫眾生善根狹小，受法之器猶如毛孔，是故就名心毛孔，經亦入身中令其發心。「是故」下結，以能廣益，名大涅槃。

The preceding section discussed eradicating transgressions; in the second section on causing people to generate the resolve, it first praises the excellence of the sūtra, first with a metaphor and then with the application; from "Why?" onward, it explains that because it causes people to generate the resolve, it is therefore supreme. The statement "enters all the pores of sentient beings" means that ordinary sentient beings have narrow and small wholesome roots, and their capacity as vessels for receiving the Dharma is like a pore; therefore, it is termed the 'pore of the mind,' and the sūtra also enters their bodies to cause them to generate the resolve. From "Therefore" onward concludes that because it can broadly benefit, it is named Great Nirvāṇa.