妙法蓮華經文句 7.9

7.9

「爾時無數億種」乃至「而聽法」，此中第三，合上第一山川譬。攬果報而有眾生，如依山川得有世界等。百千萬億者，即是十法界眾生也。今正語七方便眾生差別，配如上說。或從「汝等天人」者，皆合山川譬也。

From "At that time, countless myriads of kinds" up to "and listened to the Dharma": here is the third [part], matching the first [element] above, the parable of the mountains and rivers. Gathering retribution results in sentient beings, just as relying on mountains and rivers results in worlds and so forth. "Hundreds of thousands of myriads of koṭis" refers to the sentient beings of the ten dharma realms. Now it directly speaks of the differences among the sentient beings of the seven expedients, correlated as stated above. Or, from "You devas and humans" onward, all matches the parable of the mountains and rivers.