摩訶止觀 5.191

5.191

經云：「生亦不可說，以生無故。」今解：此破不思議惑。界內生生亦是生，界外不生生亦是生，祇是無明之生。生必託緣生；緣生即空即中，心行處滅，言語道斷，故不可說也。

The sūtra says: "Arising is also ineffable, because arising is non-existent." It is now explained: this breaks inconceivable afflictions. Arising arising within the realms is also arising; non-arising arising outside the realms is also arising; both are simply the arising of avidyā. Arising must depend on conditions to arise; arising from conditions is identical to emptiness and identical to the middle; the locus of mental activity is extinguished, and the path of speech is cut off; therefore it is ineffable.