維摩經玄疏 6.50

6.50

Third, clarifying the four gates entering the substance: seeking the substance of the true nature and true mark, it is profoundly subtle and uniquely transcendent; none in all the worldly realm can tally with it. But because the Great Sage clearly surveyed the gates leading to the principle, he thereupon, regarding the ineffable principle, initiated teaching to meet conditions, taking the teaching as the gate. Therefore, those who receive the teaching tally with the principle by way of the gate. Hence the Lotus Sūtra states: "By the Buddha's gate of teaching, they escape the suffering of the three realms," and it also says: "Its gate of wisdom is difficult to understand and difficult to enter." This sūtra's clarifying the various bodhisattvas each speaking of entering the dharma-door of non-duality is precisely this intent. Now I will briefly explain this through three points: first, briefly discerning the characteristics of the four gates; second, directly clarifying the four gates entering the substance; third, clarifying the siddhāntas giving rise to the teaching of the four gates.