法華義疏 8.98

8.98

二科互有開合不同，五乘即開淺合深，三草二木即開深合淺。開淺合深者，開小草為天人兩乘，開中草為聲聞緣覺二也。合深者，總合大乘因果悉入佛乘也。

The two categories differ in opening and combining with respect to one another: the five vehicles open the shallow and combine the deep, whereas the three grasses and two trees open the deep and combine the shallow. Opening the shallow and combining the deep means: opening the small grass into the two vehicles of devas and humans, and opening the middle grass into the two of śrāvakas and pratyekabuddhas. Combining the deep means: comprehensively combining the cause and fruition of the Mahāyāna, all entering into the Buddha vehicle.