大毘盧遮那成佛經疏 2.70

2.70

第四十一「云何窟心？謂順修為入窟法」者，謂諸龍、阿修羅等，皆在地下或海底深窟中。多有神仙諸藥，能得長壽自在。行者或念彼中多有美女，端正同於諸天，可無夭逝之憂，五欲自恣。或念留住彼中，可得劫壽見未來諸佛。皆是窟心也。當念如法修行，可於此生見法明道乃至成佛，不應抂路稽留念此世仙之法，是彼對治。

The forty-first: "What is the cave mind? It is following practice to enter a cave." This refers to nāgas, asuras, and the like, who all dwell in deep caves beneath the earth or under the sea, where there are many ṛṣi herbs that grant longevity and mastery. The practitioner might think that there are many beautiful women there, fair as goddesses, free from the worry of untimely death, and indulge freely in the five desires; or they might think that by staying there, they could attain a lifespan of a kalpa and see future buddhas. These are all the cave mind. Reflecting that by practicing in accordance with the Dharma one can realize the Dharma, clarify the Path, and even attain buddhahood in this very life, and that one should not make a detour and linger to pursue the ways of worldly ṛṣis, serves as its antidote.