維摩經玄疏 6.57

6.57

Second, clarifying the four gates of the shared teaching: this is the Dazhidulun clarifying: "All is real, all is unreal, all is both real and unreal, all is neither real nor unreal"; regarding these four propositions, the Buddha extensively explained the supreme-meaning siddhānta. The Madhyamakaśāstra clarifies that these four propositions are all called the true mark of all dharmas; these are the four propositions of embodying dharmas as immediately empty in the shared teaching's clarification of dharmas of correct causes and conditions as dreams, illusions, echoes, transformations, the moon in the water, and images in a mirror. If the three vehicles together receive this teaching, but their faculties and conditions are different, each enters the supreme meaning at one proposition; hence all four propositions are called gates. This is detailed as in Piṅgala's commentary. The commentary also says: "The true mark of all dharmas has three kinds." Thus we know that these four gates are the four gates through which the three vehicles together enter, seeing the supreme meaning.