大般涅槃經義記 9.73

9.73

四明業定，老少作業無互受過。「小時作業應小受」等，明少作業無互受過。「老時作」等，明老作業無互受過。先就惡業難無少受，「老時作惡生地獄中，初生之時不應受苦，至老方受」，初生即受，明業不起。下就善業難無少受，「老時不殺，至後身中不應有其壯年之壽。若無壯壽，云何至老？業不失故」，舉因顯果。

Fourth, it clarifies that if karma were determinate, there would be the fault that karma performed in old age and youth could not be experienced mutually. 'Karma performed when young should be experienced when young', etc., clarifies the fault that karma performed in youth cannot be experienced [in old age]. 'Performed when old', etc., clarifies the fault that karma performed in old age cannot be experienced [in youth]. First, regarding unwholesome karma, it objects to the lack of experiencing it in youth: 'performing evil when old and being born in hell, at the time of initial birth one should not experience suffering, but only experience it upon reaching old age'; [yet] one experiences it upon initial birth, clarifying that karma does not fail to arise. Below, regarding wholesome karma, it objects to the lack of experiencing it in youth: 'not killing when old, in a future body one should not have the lifespan of prime manhood. If one has no prime lifespan, how could one reach old age? Because karma is not lost', adducing the cause to manifest the fruit.