俱舍論頌疏論本 24.11

24.11

此即第三向者，即此斷七八品惑，名不還向，趣不還果故。

As for 'This is the candidate for the third': precisely this abandonment of seven or eight categories of defilement is called the candidate for non-returner, because one is proceeding toward the fruit of non-returner.