俱舍論疏 12.23

12.23

論「謂此世間至壞劫便至」，明住劫後有壞劫也。住劫「二十中劫」者，謂刀、兵等中二十也。壞劫言「等住」者，於壞劫無刀、兵等劫，但住劫時等，名等住劫。此即住、壞、空、成各二十劫，合八十中劫為一大劫。

On the Śāstra's words, "Namely, this world [...] the eon of destruction then arrives": Explaining that after the eon of abiding (sthiti-kalpa) there is the eon of destruction. In the eon of abiding, "twenty intermediate eons" refers to the twenty intermediate eons of swords and weapons, etc. Regarding the eon of destruction, it is called "equally abiding" because in the eon of destruction there are no eons of swords and weapons, etc.; it is only that the time is equal to the eon of abiding, so it is named the eon of equal abiding. Thus abiding, destruction, emptiness, and formation each have twenty eons, combining eighty intermediate eons to make one great eon.