大般涅槃經義記 8.3

8.3

前中，初先開列二門，「終不定說心有淨性」是其一門，「及不淨性」復為一門。次總釋之，「淨、不淨性無住處故」，不作定說。下別釋之，「從緣生貪，故說非無」明無淨性，「本無貪性，故說非有」明無染性。

In the former part, first two gates are set out: "never definitively saying that the mind has a pure nature" is one gate; "and an impure nature" is another gate. Next, it generally explains them: because "the pure and impure natures have no abiding place," no definitive statement is made. Below, it specifically explains them: "arising greed from conditions, hence it is said not to be non-existent" clarifies that it lacks a pure nature; "originally without a greedy nature, hence it is said not to be existent" clarifies that it lacks a defiled nature.