大方廣圓覺修多羅了義經略疏 1.257

1.257

從喻為名。金剛堅而復利，堅則無物可壞，利則能壞一切。此菩薩智亦爾，煩惱不能侵，外魔不能動，堅也；能破諸障，斷人疑惑，利也。故起三重甚深之難，以消末世之疑。疑心既無，即具無盡功德，故復云藏。

Named after a metaphor. A diamond is both hard and sharp: being hard, nothing can destroy it; being sharp, it can destroy everything. This bodhisattva's wisdom is also like this: afflictions cannot invade it and external māras cannot shake it—this is its hardness; being able to shatter all obstacles and sever people's doubts and perplexities—this is its sharpness. Therefore, he raises three profound objections in order to dispel the doubts of the final age. Doubts having ceased, he is endowed with inexhaustible virtues; hence he is also called 'Treasury' (garbha).