妙法蓮華經玄義 3.124

3.124

中智入空智，分別為三智者：初、依無漏，發一切智；次、依有漏，發道種智；後、深觀無漏之空，知空亦空，發一切種智。然初心不知空空。次雖得空，亦不空空。後能深觀於空，空於前空。但二空名同、二境亦合，故言相入。今若分別，以無漏空為一切智；有漏空為道種智；中道空為一切種智。世人採經論意云：六地斷惑，與羅漢齊；七地修方便道；八地道觀雙流，破無明成佛。即此意也。

Regarding the wisdom of the middle merging into the wisdom of emptiness, distinguishing them as three wisdoms: First, based on the uncontaminated, one generates the wisdom of all [phenomena]; next, based on the contaminated, one generates the wisdom of the paths; finally, contemplating deeply the emptiness of the uncontaminated and knowing that emptiness is also empty, one generates the wisdom of all modes. However, the initial mind does not know the emptiness of emptiness. Next, although one attains emptiness, one does not make emptiness empty. Finally, one is able to contemplate emptiness deeply, emptying the previous emptiness. But because the names of the two emptinesses are the same and the two objects also combine, it is said that they merge with one another. Now if we distinguish them: the emptiness of the uncontaminated is the wisdom of all [phenomena]; the emptiness of the contaminated is the wisdom of the paths; the emptiness of the middle way is the wisdom of all modes. People of the world draw upon the meaning of the sūtras and treatises, saying: 'At the sixth stage one cuts off delusion, equal to an arhat; at the seventh stage one cultivates the path of expedients; at the eighth stage the path and contemplation flow together, destroying ignorance and achieving buddhahood.' This is precisely that meaning.