佛說觀佛三昧海經 7.26

7.26

「爾時如來即便微笑，口出無量百千光明，一一光中無量化佛；一一化佛萬億菩薩以為侍從。時彼龍王於其池中，出七寶臺奉上如來：『唯願天尊！受我此臺。』爾時世尊告龍王曰：『不須此臺，汝今但以羅剎石窟持以施我。』時梵天王無數天子先入窟中，時彼龍王以諸雜寶以莊挍窟。佛告阿難：『汝教龍王淨掃石窟。』諸天聞已，各脫寶衣競以拂窟。爾時如來還攝身光，卷諸化佛來入佛頂。爾時如來，勅諸比丘皆在窟外，唯佛獨入自敷坐具，敷坐具時，令此石山暫為七寶。時羅剎女及以龍王，為四大弟子、尊者阿難造五石窟。

Then the Tathāgata smiled, and from his mouth issued boundless hundreds of thousands of rays of light. Within each ray were boundless transformation Buddhas; each transformation Buddha had tens of millions of bodhisattvas as attendants. At that time, that dragon king brought forth a seven-jeweled terrace from the pool and offered it to the Tathāgata, saying, 'May the Deva of Devas deign to accept this terrace from me!'
Then the Bhagavat said to the dragon king, 'I do not need this terrace. Now you need only give me the rākṣasa rock cave.'
Then Brahmā and countless devaputras entered the cave first. The dragon king adorned the cave with various jewels. The Buddha said to Ānanda, 'Instruct the dragon king to sweep the rock cave clean.'
When the devas heard this, each took off their jeweled robes and vied with one another to wipe down the cave. At that time the Tathāgata withdrew the light of his body and gathered all the transformation Buddhas, bringing them into the Buddha's crown. The Tathāgata then instructed the monks to remain outside the cave; only the Buddha entered alone and spread his seat himself. As he spread his seat, he caused this rocky mountain to temporarily become the seven jewels. Then the rākṣasī and the dragon king built five rock caves for the four great disciples and the venerable Ānanda.