俱舍論記 25.119

25.119

「由所信別至非證淨故」者，釋後兩句。所信不同，故名有四，實事唯二。信、戒為體，四唯無漏，以有漏法非證淨故。

Regarding "Due to the difference in what is believed [...] because they are not verified clarity": this explains the last two lines. Because what is believed in differs, there are four names, but their actual entities are only two. Faith and morality are their intrinsic natures, and all four are solely anāsrava, because sāsrava dharmas are not verified clarity.