肇論新疏 1.319

1.319

是以聖人乘千化而不變、履萬惑而常通者，以其即萬物之自虛，不假虛而虛物也。

Therefore, that the sage mounts the thousand transformations without changing, and treads the myriad delusions while remaining ever unobstructed, is because he identifies with the intrinsic unreality of the myriad things, not borrowing unreality to make things unreal.