楞伽阿跋多羅寶經註解 4.199

4.199

此言沙性不壞，喻如來法身常住。言是地自性者，有事有理。以事則同一堅性，故為沙為石；以理則與彼堅、濕、煖、動均一真性。故劫盡燒時而地性自若，蓋地與火大俱是生故。愚夫不知見，謂燒爾。火因者，以地無火而不燒，火無地而不續，故地不得而燒。如來法身不遷不變亦復然也。

This states that the nature of sand is indestructible, illustrating that the Tathāgata's dharmakāya is eternally abiding. In stating that it has the intrinsic nature of earth, there is both a phenomenal and a principle aspect. In terms of phenomenon, they share the identical nature of solidity, thus becoming sand or stone. In terms of principle, it shares an identical true nature with the solid, wet, warm, and motile [elements]. Therefore, when the eon is consumed at its end, the nature of earth remains just as it was, because the earth and fire elements are both arisen together. Foolish people do not understand this vision and say that it burns. As for 'due to its cause in fire': because earth without fire would not burn, and fire without earth would not continue, earth cannot be burned. The Tathāgata's dharmakāya being unmoving and unchanging is also like this.