仁王經疏 3.437

3.437

釋曰：第三：釋勸所由。文別有二：初明三世諸王福有興衰、後明未來護持大作利益。此即初也。

The explanation says: Third: explaining the reasons for the encouragement. The text has two distinct parts: first, clarifying that the blessings of the kings of the three times have rise and decline; later, clarifying that in the future, protecting and upholding it will produce great benefit. This is the first.