法華玄義釋籤 16.30

16.30

觀無常即是觀空因緣，猶如觀色念念無常即知為空，過去色壞故不可見，故無色相；未來色不生無作無用不可見故，故無色相；現在無住故不可見不可分別，故無色相。無色相故是空無生滅，無生滅及以生滅其實是一，說有廣略耳。

Contemplating impermanence is precisely the cause and condition for contemplating emptiness. Just as in contemplating form, [seeing that it is] impermanent from thought-moment to thought-moment, one immediately knows it to be empty: past form is destroyed and therefore cannot be seen, so there is no mark of form; future form is unproduced, devoid of action and devoid of function, and because it cannot be seen, there is no mark of form; present [form] has no abiding, and because it cannot be seen or distinguished, there is no mark of form. Because there is no mark of form, it is empty and devoid of arising and ceasing. Non-arising and ceasing and arising and ceasing are actually one; they are spoken of merely in terms of broadness and brevity.