俱舍論記 12.17

12.17

「此後復有至成已住劫」者，此明中劫并顯住劫。准此論文，壽漸減時方名住劫，壽未減時是成劫攝。問：初劫唯減、後劫唯增，如何時等中間十八？解云：二十住劫前後相望，前有情福勝、後有情福劣，住中初劫福最勝故，應合受用上妙境界，故下時極遲。從第二劫已去，其福漸薄，上稍遲、下漸疾。以上時境勝，由薄福故，不合受用，故上時遲。以下時境劣，由薄福故，應合受用，故下時疾。如是乃至第十九劫福漸漸薄，上時極遲、下時極疾。至第二十劫福最薄故，上時極遲。故初、後劫等中十八。又解：壽未減時是成劫攝，從無量歲初減已去方名住劫。第二十劫上至八萬，多時經停，故初、後劫等中十八。

"After this there is further... up to: the kalpa of duration after having formed": This explains the intermediate kalpas and also reveals the kalpa of duration. According to this text, only when the life-span gradually decreases is it called the kalpa of duration; when the life-span has not yet decreased, it is included within the kalpa of formation. Question: The first kalpa is only decreasing, and the last kalpa is only increasing; how can their time be equal to the intermediate eighteen? Answer: When comparing the twenty kalpas of duration earlier and later, the merits of earlier sentient beings are superior, while the merits of later sentient beings are inferior. Because merits are supreme in the first kalpa of duration, they are entitled to enjoy superior and marvelous realms; hence, the time of decreasing is extremely slow. From the second kalpa onward, their merits gradually diminish; the increase is slightly slower, and the decrease is gradually faster. Because the realms during the time of increase are superior, due to deficient merit they are not entitled to enjoy them, so the time of increase is slow. Because the realms during the time of decrease are inferior, due to deficient merit they are entitled to enjoy them, so the time of decrease is fast. In this manner, up to the nineteenth kalpa, merits become increasingly deficient; the time of increase is extremely slow, and the time of decrease is extremely fast. Reaching the twentieth kalpa, merits are the most deficient; hence the time of increase is extremely slow. Therefore, the first and last kalpas are equal to the intermediate eighteen. Another explanation: The time before the life-span decreases is included within the kalpa of formation; only from the initial decrease from an immeasurable life-span onward is it called the kalpa of duration. In the twentieth kalpa, it increases up to eighty thousand [years] and remains for a long time; therefore, the first and last kalpas are equal to the intermediate eighteen.