金剛經纂要刊定記 5.280

5.280

猶如下。喻明也。意顯精純故名真金。謂眾生如全鑛，菩薩如金鑛相半，佛如純金也。然金性本有，鍊之則純，如體本然，修之則淨。故《圓覺》云：「譬如銷金鑛，金非銷故有，雖復本來金，終以銷成就，一成真金體，不復重為鑛。」

"Just as..." and so forth clarifies by metaphor. The intention is to reveal that because it is refined and pure, it is called true gold. It means that sentient beings are like unrefined ore, bodhisattvas are like gold and ore half-mixed, and Buddhas are like pure gold. Yet the nature of gold is fundamentally present, and when smelted it becomes pure; the substance of tathatā is fundamentally so, and when cultivated it becomes pure. Therefore the Sūtra of Complete Enlightenment says: "For example, when melting gold ore, the gold does not come to exist because of the melting; although it is fundamentally gold, it is ultimately brought to completion through melting; once the substance of true gold is formed, it does not become ore again."