法華玄義釋籤 1.64

1.64

「大事」下明說本意，意在佛乘，故舉始終意在佛慧，中間調斥非佛本懷，故云「助顯」。

From "the great matter" downward, it clarifies the original intent of preaching: the intent lies in the Buddha vehicle, and therefore by presenting the beginning and the end, the intent lies in the Buddha's wisdom; the interim seasoning and reproaching were not the Buddha's original intent, and so it says "aiding the revelation."