法華義疏 3.17

3.17

二者、說於三乘為令眾生悟入一乘，故此三乘為趣一乘之由漸，故名方便。如下文云「我設是方便令得入佛慧」，又云「我此九部法入大乘為本」，故說三乘為一乘之方便也。三者、合前二義圓成一旨，所以無三說三者，欲令因三悟不三，是以二言合成一意也。

Second, expounding the triyāna is in order to cause sentient beings to awaken to and enter the ekayāna; thus this triyāna serves as the graduated path toward the ekayāna, and is therefore called upāya. As a subsequent passage says, "I establish this upāya to cause them to enter the Buddha's wisdom"; and it also says, "My teachings of these nine divisions have entering the Mahāyāna as their foundation." Therefore, expounding the triyāna is the upāya for the ekayāna. Third, combining the preceding two meanings completely establishes a single purport: the reason for speaking of three when there are no three is to desire that through the three they awaken to the non-three; thus the two statements combine to form a single intention.