俱舍論記 5.127

5.127

「壽盡位中至俱盡故死」者，重釋第三句。二業中感壽業勝。於第三句壽盡死中，福盡於死雖復無能，以壽盡時自然死故。然說為俱盡故死者，為壽盡時福亦盡故。故俱盡時有死，說為俱盡故死。又解通伏難。伏難意云：福盡壽未盡容有受苦而活，壽盡福未盡必無更活，故知俱盡之時福盡於死無能，應言壽盡故死，不應言福盡故死。為通斯難，故有此文。福盡於死實無功能，但為於俱盡位有死，說為俱盡故死。

"In the state of the exhaustion of life… death due to the exhaustion of both" is a re-explanation of the third alternative. Between the two kinds of karma, the karma that brings about life is predominant. In the third alternative of death through the exhaustion of life, although the exhaustion of merit has no efficacy with respect to death, because at the exhaustion of life death occurs naturally, it is nonetheless spoken of as death due to the exhaustion of both because at the time life is exhausted, merit is also exhausted. Therefore, since there is death when both are exhausted, it is spoken of as death due to the exhaustion of both. Another explanation resolves a latent objection. The intent of the latent objection is: When merit is exhausted but life is not yet exhausted, it is possible to live while undergoing suffering; when life is exhausted but merit is not yet exhausted, it is impossible to live any further. Hence we know that when both are exhausted, the exhaustion of merit has no efficacy with respect to death; one ought to say death due to the exhaustion of life, not death due to the exhaustion of merit. It is to resolve this objection that this text exists. The exhaustion of merit truly has no efficacy with respect to death; it is simply because there is death at the state where both are exhausted that it is spoken of as death due to the exhaustion of both.