說無垢稱經疏 5.101

5.101

〈方便品〉下，合有五品明利他行。初之四品，隱迹利他，未現大神通，隨類濟物，故名隱迹利他，密權也。此之一品，現大神通，明顯迹利他，顯權也。神通妙用上位能知，故非下心之所思慮，亦非下言之所議度。今此廣明，名不思議品。此以無漏慧根為性，不思議體即神通故。其通之境妙用亦難測，亦名不思議。

From the "Chapter on Upāya" onwards, there are five chapters in total that elucidate the practice of benefiting others. In the first four chapters, they benefit others while concealing their traces; having not yet manifested great supernormal powers, they deliver beings according to their capacities, and hence it is called "benefiting others with traces concealed"—this is secret expedient means. In this single chapter, they manifest great supernormal powers, openly revealing their traces to benefit others—this is open expedient means. Because the subtle operations of supernormal powers can only be known by those of higher stages, they cannot be thought of by inferior minds, nor can they be deliberated upon by inferior words. Now this is explained in detail, and so it is called the "Chapter on the Inconceivable." This has the faculty of unpolluted wisdom as its intrinsic nature, because the essence of the inconceivable is supernormal power itself. The subtle operation of the sphere of these supernormal powers is also difficult to fathom, and so it is also called "inconceivable."