法華論疏 3.121

3.121

云方便令入涅槃城故者，論意明欲令其人前知世間非是真城，方便說小乘涅槃以為真城，然後始令捨小城入大乘涅槃城也。

Saying "by skillful means to cause them to enter the city of nirvāṇa" means: the treatise's intent clarifies that, wishing to cause that person to first know that the worldly is not a real city, he skillfully taught the Hīnayāna nirvāṇa as a real city, and only thereafter caused them to abandon the small city and enter the Mahāyāna city of nirvāṇa.