大般涅槃經義記 6.114

6.114

就明無相有得之中，先明道等無相而有，「如其無」下就有明得。前中，初法，次喻，後合。合中具三，法說文中但明其道，餘略不論。「道之性相實不生滅，不可捉持」明道無相，「雖無色」下明其有用。道實有體，體相難彰，舉用顯之，故言有用。

Regarding the explanation that it is markless and yet exists, it first explains that the Path and so forth are markless yet existent; from "if it were nonexistent" onward, on the basis of its existence, it explains attainment. In the former, there is first the dharma, next the analogy, and then the application. The application contains all three, whereas the text stating the dharma explains only the Path, omitting the rest. "The nature and marks of the Path are truly neither arising nor ceasing, and cannot be grasped" explains that the Path is markless; from "although it has no form" onward, it explains that it has function. The Path truly has an essence; its essential marks being difficult to manifest, it cites its function to reveal it; hence it is said to have function.