佛說觀佛三昧海經 7.26

7.26

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.