The Long Āgama Sūtra 3.12

3.12

「時，忉利天作是說言：『若使世間有八佛出者，當大增益諸天眾，減損阿須倫眾。』時，忉利天言：『且置八佛，正使七佛、六佛，乃至二佛出世者，亦大增益諸天眾，減損阿須倫眾，何況八佛？』時，釋提桓因告忉利天言：『我從佛聞，親從佛受，欲使一時二佛出世，無有是處。但使如來久存於世，多所慈愍，多所饒益，天人獲安，則大增益諸天，減損阿須倫眾。』」

“The Trāyastriṃśa gods then said, ‘Whenever there are eight Buddhas who arise in the world, the host of gods would increase greatly, and the host of asuras would diminish!’

“The Trāyastriṃśa gods also said, ‘Setting aside eight Buddhas, even if seven, six … two Buddhas were to arise in the world, the host of gods would increase greatly, and the host of asuras would diminish. How would it be if there were eight Buddhas?’

“Śakra the Lord of Gods told the Trāyastriṃśa gods, ‘I’ve heard it from the Buddha, personally received it from him, that it’s impossible for two Buddhas to arise in the world at the same time. If the Tathāgata simply remained in the world for a long time, he would have compassion for many and benefit many. Gods and humans would win their peace. The host of gods would increase greatly, and the host of asuras would diminish.’”