法華玄論 9.59

9.59

答：淨土多門，下明異質同處義，故淨土不毀、穢土被燒；今明同質同處義，故三變而成淨。同質者，一淨質。一處者，無兩質共處也。

Answer: There are many approaches to the pure land. Below, it clarifies the meaning of different qualities in the same place; hence the pure land is not destroyed while the defiled land is burned. Here, it clarifies the meaning of the same quality in the same place; hence it is transformed three times to become pure. "Same quality" means a single, pure quality. "Same place" means that two qualities do not coexist in the same place.