三彌勒經疏 1.244

1.244

經曰「彌勒佛住」以下，第三讚佛壽量。《大成佛經》云「壽命具足八萬四千歲，無有中夭」，而今此經云「六萬歲」者，解云：彌勒佛壽雖八萬四千年，但受三分二，捨第三分、二萬四千壽故，故但六萬。如釋迦佛不受第三分，但受八十。是故《大集經》言「諸佛皆捨第三分」也。

From the sūtra passage stating, "The Buddha Maitreya remained," onward is the third, praising the Buddha's lifespan. The Great Attainment of Buddhahood Sūtra says: "His lifespan is fully eighty-four thousand years, with no premature death"; yet this present sūtra says "sixty thousand years." The explanation is: although the Buddha Maitreya's lifespan is eighty-four thousand years, he only accepts two of the three parts, relinquishing the third part—a lifespan of twenty-four thousand—and therefore it is only sixty thousand. Just as Śākyamuni Buddha did not accept the third part, accepting only eighty [years]. Therefore the Mahāsaṃnipātasūtra states: "All Buddhas relinquish the third part."