四明十義書 1.192

1.192

至十乘中，用於妙觀，觀此能造一念陰心本具三千。既一念即三千、三千即一念，言慮不及，故轉名不思議境也。

When it comes to the ten vehicles, one employs wondrous contemplation to contemplate this single thought-moment of the aggregate-mind, which is that which produces, as fundamentally possessing the three thousand. Since a single thought-moment is the three thousand and the three thousand are a single thought-moment, beyond the reach of speech and thought, it is renamed the inconceivable object.