法華義疏 2.57

2.57

「佛說是經已」下，第三、入定序，有四句：初、結前生後明入定時節也。「結跏趺坐」者，明入定之緣也。

From 'When the Buddha had preached this sūtra' onward is, thirdly, the preface on entering samādhi, which has four clauses: First, concluding what precedes and giving rise to what follows, it clarifies the time of entering samādhi. 'Sitting cross-legged' clarifies the circumstance for entering samādhi.