佛說觀佛三昧海經 7.27

7.27

At that time, the Bhagavat sat in the dragon king's cave without shifting from his seat; yet he also accepted the king's invitation to enter the city of Nagarahāra. At Gṛdhrakūṭaparvata, in the country of Śrāvastī, at the city of Kapilavastu, and in all his dwelling places, a Buddha was seen. Boundless transformation Buddhas sat on lotus seats in the sky, and all worlds were filled with transformation Buddhas. The dragon king rejoiced and made a great vow: 'May I, in a future life, attain Buddhahood like this!'
After the Buddha had accepted the king's invitation for seven days, the king dispatched a man riding an elephant capable of traveling eight thousand li, carrying various offerings to make offerings to the saṅgha across all lands. Everywhere he went, he saw Śākyamuni Buddha. The messenger returned and reported to the king, 'The Tathāgata, the Bhagavat, is not only in this country—he is also in other countries! In other countries, all the Buddhas are preaching suffering, emptiness, impermanence, non-self, and the six pāramitās.'
When the king heard these words, his mind opened in sudden awakening and he attained the patience of the non-arising of dharmas.