妙法蓮華經玄義 2.39

2.39

此《法華經》明九種性相，皆入即空、即假、即中。汝實我子，我實汝父，一色一味，純是佛法，更無餘法故，知佛界最為無上。復次，餘經所明九性相，不得入佛性相即空、即假、即中者，此經皆開方便，普令得入。又按其相性，即是即空、即假、即中，不論引入，是故如來殷勤稱歎此《法華經》最為無上，意在此也。

This Saddharmapuṇḍarīka-sūtra clarifies that the nine kinds of natures and marks all enter into the identical-with-emptiness, identical-with-provisionality, and identical-with-the-middle. "You are truly my sons, and I am truly your father." Of one color and one taste, it is purely the Buddha-Dharma with no other dharma remaining; thus one knows that the Buddha realm is supreme above all. Furthermore, regarding what the other sūtras clarified of the nine natures and marks—that they could not enter the Buddha nature and marks of the identical-with-emptiness, identical-with-provisionality, and identical-with-the-middle—this sūtra opens expedient means across them all, universally causing them to enter. Moreover, considering their marks and natures, they are themselves identical with emptiness, identical with provisionality, and identical with the middle, without needing to speak of leading them in. For this reason, the Tathāgata diligently praised this Saddharmapuṇḍarīka-sūtra as supreme above all; the meaning lies precisely in this.