金剛經纂要刊定記 7.45

7.45

為示下。正顯住意。意以界喻真身，塵喻化身也。塵因界碎故非異，喻從真起應也。塵細界麁故非一，喻真實應假也。

From "In order to show..." onward directly displays the intention of abiding. The intention is to use the realm as a metaphor for the true body, and the particles of dust as a metaphor for the transformation body. The dust arises from crushing the realm, and is therefore not different, serving as a metaphor for arising the response from the real. The dust is fine and the realm is gross, and they are therefore not one, serving as a metaphor for the real being true and the response being provisional.