仁王護國般若波羅蜜多經疏 2.39

2.39

問：前空空與此空空何別？答：前破諸法故云空空，此破前空故名空空。若爾，由諸法有破故云空。空既非法，空何所破？答：破諸法已唯有於空，空亦應捨故須空空。如藥治病，病盡捨藥。藥若不捨，藥復成病。恐空成病，以空捨空，故云空空。從此第二諸法假有。於中分二：初明諸法有、後明我法空。初諸法有，於中分三：且初第一標諸法有。

Question: What is the difference between the earlier emptiness of emptiness and this emptiness of emptiness? Answer: The earlier one refuted all phenomena, hence it was called the emptiness of emptiness; this one refutes the preceding emptiness, hence it is named the emptiness of emptiness. If so, because phenomena exist they are refuted, and thus called empty. Since emptiness is not a phenomenon, what does emptiness refute? Answer: Having refuted all phenomena, there is only emptiness; emptiness must also be abandoned, hence the emptiness of emptiness is necessary. Just as medicine cures an illness and when the illness is gone the medicine is discarded: if the medicine is not discarded, the medicine in turn becomes an illness. Fearing that emptiness may become an illness, one discards emptiness with emptiness; therefore it says "the emptiness of emptiness." Next is the second [section], the provisional existence of phenomena. This is divided into two: first, clarifying that phenomena exist; later, clarifying the emptiness of self and phenomena. The first part, that phenomena exist, is divided into three: first, positing that phenomena exist.