十不二門指要鈔 1.112

1.112

First, mutual fusion. The substances and natures of the three dharmas each possess the three thousand and originally subsume one another. Although it was previously understood that the mind subsumes everything, now when contemplation accords with the nature, its embracement and subsumption are clear and evident; hence from 'This being so...' onward, it first clarifies that the internal mind fuses with external dharmas. Since it says 'mutually subsuming', this is also true of sentient beings and Buddhas; hence from 'the ten directions...' onward, it next clarifies that sentient beings and Buddhas each pervade and fuse. Furthermore, this substance of nature does not mean a single nature, but rather the nature of the three thousand. Only because the Buddha possesses the three thousand does he subsume the mind and sentient beings; only because sentient beings possess the three thousand do they fuse with the mind and the Buddha. When the mind possesses the three thousand, how could it be separated from sentient beings and the Buddha? If the mind lacked the Buddha-nature, how could it subsume the Buddha? If the Buddha lacked the nature of sentient beings, how could he subsume sentient beings? Therefore, as for the statement that 'the substance of nature is without distinction', who does not know it? But the words 'all pervade everything' require deep reflection on their profound import. The other explanation, which solely discusses fusing the external to return to the internal and names this 'nondual'—how narrow it is! How could they account for 'all pervade everything'? Moreover, the remaining nine gates would all fall to one side, completely damaging the overall framework."