佛祖統紀 1.87

1.87

Next, he encountered Krakucchanda Buddha, whose lifespan was fifty thousand years; that Buddha prophesied to me: 'In a future life, you shall attain Buddhahood.' Next, he encountered Kanakamuni Buddha, whose lifespan was forty thousand years; that Buddha prophesied to me: 'In a future life, you shall attain Buddhahood.' Next, he encountered Kāśyapa Buddha, whose lifespan was twenty thousand years; that Buddha prophesied to me: 'In a future life, you shall attain Buddhahood, named Śākyamuni.' (The four Buddhas above appeared successively during the ninth decrement kalpa of the twenty kalpas of the abiding period in the Auspicious Kalpa; therefore, this text generally refers to 'a future life.') Having thus attended upon the Buddhas and cultivated the mind of a Buddha, I was then born into the Tuṣita Palace and resided in the position of being one birth away from Buddhahood. (All the above is from the Bodhisattvacaryā-sūtra. The Nirvāṇa-sūtra says that because this heaven is the supreme among the desire realm, all bodhisattvas one birth away from Buddhahood manifest birth therein in order to instruct and transform sentient beings). Now I have appeared in the world when human life is one hundred years, with slight increases and many decreases (Madhyamāgama). Śākya ought to have appeared when human life was ten thousand years, but seeing that sentient beings had no capacity to be saved, he waited until it was one hundred years, when seeing them oppressed by suffering and the kalpa approaching its end, he appeared in the world (Dazhidulun. All the above are passages clarifying the origin and traces for those of lesser capacity).