維摩經玄疏 5.5

5.5

First, the name sūtra containing the sense of "root of dharmas": the Great Sage knows that all is ineffable, yet through the causes and conditions of the four siddhāntas there are spoken teachings. If spoken through the mundane siddhānta, it is the root of all treatises; if spoken through the for-persons and curative siddhāntas, it is the root of practice; if spoken through the paramārtha siddhānta, it is the root of principle. Therefore sūtra contains the sense of "root of dharmas".