俱舍論記 23.125

23.125

「此預流名至故名預流」者，答。此預流名目初得果，不目第八。然依遍得一切四果者初所得果，建立此名。一來、不還非定初得，雖超越者有初得義，若次第者即非初得。此若得時決定初得，故名預流。

Regarding the passage [beginning with] "This name 'stream-enterer' [...] therefore called a stream-enterer": This is the answer. This name "stream-enterer" designates the fruit first attained; it does not designate the eighth [person]. Rather, this name is established based on the fruit first attained by one who progressively attains all four fruits. [The fruits of] once-returner and non-returner are not necessarily attained first: although in one who leaps over [stages] there is the sense of first attainment, in one who proceeds sequentially it is not a first attainment. When this [fruit of stream-entry] is attained, it is definitely attained first; therefore it is called stream-entry.