法華玄論 2.117

2.117

二明此華由種而生，喻一乘從緣而起。故下偈云「佛種從緣起，是故說一乘。」

Second, it clarifies that this flower arises from a seed, illustrating that the one vehicle arises from conditions. Therefore a verse below says: "The Buddha-seed arises from conditions; / therefore the one vehicle is spoken."