大般涅槃經義記 7.82

7.82

第五難中，句別有四：一立等喻，「譬如虛空等無障礙，故名為常」；二約喻徵法，「若涅槃等，何故眾生有得、不得」責其不等，「若不等」下以其不等結成無常；三重立等喻；四約喻徵法，「若涅槃等，一人得時多人應得、一人斷結多人亦斷」徵令齊等，「若不如是，云何名常」以其不等徵破常義。

Regarding the fifth objection, there are distinctively four clauses: first, establishing an analogy of equality: "just as space is equal and unobstructed, and is therefore called permanent"; second, applying the analogy to interrogate the dharma: "if nirvāṇa is equal, why do sentient beings have attainment and non-attainment?"—demanding why it is unequal; from "if it is not equal" downward, through its inequality concludes that it is impermanent; third, re-establishing an analogy of equality; fourth, applying the analogy to interrogate the dharma: "if nirvāṇa is equal, when one person attains it, many people ought to attain it; when one person severs the fetters, many people should also sever them"—interrogating in order to demand equal parity; "if it is not like this, how can it be called permanent?"—through its inequality, interrogates and refutes the meaning of permanence.