俱舍論疏 6.268

6.268

論「同類遍行至皆似因故」，釋第三句。同類、遍行因俱是相似，力用少異，分為二因。果但酬因不辨力用，但據似因，名等流果。後等前流，名為等流，等流即果，名等流果。

On the Śāstra's statement, "Because homogeneous and universal [causes]… all resemble their causes": This explains the third line. Homogeneous and universal causes both resemble [their results]; their efficacies differing slightly, they are divided into two causes. The fruit merely requites the cause without discerning efficacy; solely in terms of resembling the cause, it is called an outflow result. The subsequent flows equally with the antecedent, hence it is called "equal flow" (niṣyanda); the equal flow is itself the fruit, hence it is called the outflow result.