俱舍論記 25.51

25.51

「若爾應釋至是阿羅漢」者，說一切有部復引經難。若說應果定不退者，應釋炭喻契經中文。此經既言：諸聖弟子有時失念生不善覺。明知應果亦容有退。如何得知彼是應果？此經唯說阿羅漢故。復以何文證知應果？由此炭喻契經中言：彼聖弟子心於長夜隨順遠離等。既言隨順遠離，明知即是阿羅漢果。復如何知隨順遠離是阿羅漢？餘契經中有即說此順遠離等名應果力。又此炭喻經說彼聖弟子於一切順漏已能永吐，顯能永斷一切有漏。已得清涼，顯彼已得清涼涅槃。由此定知炭喻經說是阿羅漢。

"If so, you must explain […] is an arhat": the Sarvāstivāda further cites a sūtra to object. If you say that the fruit of the arhat definitely does not fall away, you must explain the text of the Charcoal Simile Sūtra (Aṅgāropama-sūtra). Since this sūtra says, 'Noble disciples sometimes lose mindfulness and give rise to unwholesome thoughts,' it is clearly known that the fruit of the arhat also admits of falling away. How is it known that that is the fruit of the arhat? Because this sūtra speaks exclusively of arhats. Furthermore, by what text is the fruit of the arhat proven and known? Because this Charcoal Simile Sūtra says: 'That noble disciple's mind has for a long night conformed to seclusion, and so forth.' Since it says 'conformed to seclusion', it is clearly known to be the fruit of the arhat. How is it further known that 'conforming to seclusion' is an arhat? In other sūtras, this 'conforming to seclusion and so forth' is stated to be the power of an arhat. Furthermore, this Charcoal Simile Sūtra says that that noble disciple has already been able to vomit up completely all that conforms to contamination, showing that they are able to sever all contaminations forever. 'Has already attained coolness' shows that they have already attained cool nirvāṇa. From this it is definitely known that the Charcoal Simile Sūtra speaks of an arhat.