俱舍論疏 6.277

6.277

「論曰至有異熟果」，此第一異熟果相。「無覆無記法中有異熟」者，明性唯是無覆無記。若異熟果是其善惡，即所造業無受盡期，故異熟果唯是無覆無記中攝。

The commentary states: "…there is retributive result": This is the first, the characteristic of the retributive result. "Among non-obscured morally neutral phenomena there is retribution" clarifies that its nature is solely non-obscured morally neutral. If the retributive result were good or bad, then for the karma created there would be no time when its experiencing would end; therefore the retributive result is comprised solely within non-obscured morally neutral phenomena.