大般涅槃經義記 4.52

4.52

The above established the simile; below, it correlates and reveals the dharma, only correlating the first pair, while the subsequent can be known by analogy. 'Clarity and ignorance are also like this' correlates with the preceding eating of grass and blood turning into milk, revealing the duality of dharma-characteristics. From 'if together with the defilements and fetters' downward correlates with the preceding 'although this milk comes from grass and blood it cannot be [called] two' and so forth. Therein, it first directly explains non-duality: the single substance of buddha-nature, when together with the fetters, is called ignorance; when together with wholesome dharmas, it is called clarity; the essential nature of clarity and ignorance is non-dual. What is this essential substance? It refers to the true consciousness-mind. Thus in the Daśabhūmika Sūtra it is said that the twelve links of dependent origination are all made by the true mind, just as what is done in a dream is all made by the retributive mind. From 'therefore' downward, it concludes non-duality; from 'due to these conditions' downward, it concludes and correlates with the preceding simile: because of the two conditions of clarity and ignorance, I previously spoke of the rich grass of the Snowy Mountains, which if eaten by cows immediately becomes clarified butter. 'Buddha-nature is also like this' cites the dharma to correspond; this reveals that buddha-nature is identical to that rich grass and clarified butter in having one nature prior and subsequent; hence it says 'is also like this'. Because the nature is one, when that ignorance transforms, it immediately becomes clarity. Thus all the four noble truths up to here properly explain the practice of realization.