維摩經玄疏 2.37

2.37

次釋「中道觀」者，「中」以不二為義；「道」是能通為名。照一實諦，虛通無滯，名中道觀也。故經云：「前二觀為方便道，因是二空觀，得入中道，雙照二諦，心心寂滅，自然流入薩婆若海。」

Next, explaining the "contemplation of the Middle Way": "middle" takes non-duality as its meaning; "way" takes being able to penetrate as its name. Illuminating the one real truth, opening unhindered and without obstruction, is called the contemplation of the Middle Way. Hence the sūtra states: "The prior two contemplations are the path of expedient means; by relying on these two contemplations of emptiness, one can enter the Middle Way, dual-illuminating the two truths, mind after mind quiescing, naturally flowing into the ocean of sarvajñā."