大般涅槃經義記 4.340

4.340

自下第二廣就向前中品病人別為五門對之顯佛。何故偏舉中品顯佛？以其中品是小乘人，小乘是其大乘家對，舉小彰大，明大義顯，所以偏舉。於中初先總舉五人於大有病，非是如來據小；羅漢、辟支無病，今對於大亦得有病。「何等」已下別顯五人對之顯佛，先徵、後辯。

Next, the second part broadly takes the aforementioned intermediate grade of sick people and divides them into five gates, contrasting them to reveal the Buddha. Why specifically bring up the intermediate grade to reveal the Buddha? Because the intermediate grade consists of Hīnayāna people, and the Hīnayāna is the direct counterpart to the Mahāyāna; by raising the small, the great is manifested, and the great meaning becomes clear, which is why they are specifically brought up. Therein, it first generally brings up the five people who have illness with respect to the Great [Vehicle]; it is not that the Tathāgata [has illness]. In terms of the Small [Vehicle], arhats and pratyekabuddhas have no illness, but now, when contrasted with the Great, they can also be said to have illness. From 'Which are...' onward, it specifically reveals the five people, contrasting them to reveal the Buddha, first questioning and then explaining.