法華論疏 3.88

3.88

此有二義：一者且說二乘涅槃以為真城，為治前二種人虛偽之城。二者次為此人說於化城，二乘涅槃尚是化城，汝之所得云何真實？問：經文但言說化城，云何說真城？答：《化城品》中具敘今昔，意敘昔即明是真、敘今即明是化也。「又現」下，論文也。

This has two meanings: first, provisionally speaking of the two vehicles' nirvāṇa as a real city in order to remedy the false city of the previous two kinds of persons; second, next speaking of the conjured city for this person: if the two vehicles' nirvāṇa is still a conjured city, how could what you attained be real? Question: The sūtra text only speaks of explaining the conjured city; why does it speak of explaining a real city? Answer: The "Parable of the Conjured City Chapter" fully recounts both the past and the present. The intent of recounting the past was precisely to clarify that it is real; recounting the present is precisely to clarify that it is conjured. From "Moreover, appearing" below is the treatise text.