俱舍論記 30.46

30.46

「昔我即今至曾燒彼事」者，論主難。若昔我即今我，體應常住，如何說我非是常耶？難訖通經。故說今我昔為師言，顯昔與今是一相續假者。如言此火曾燒彼事，亦顯昔火與今時火同一相續火，故言此火曾燒彼事。

Regarding 'If the self of the past is the self of the present [...] once burned that thing': the author of the treatise objects. If the past self is identical to the present self, its substance would have to be eternal; how could you say that the self is not eternal? Having concluded the objection, he resolves the sūtra. Therefore, the statement 'I now was the teacher in the past' indicates that the past and the present are a single continuum of a nominal entity. It is just like saying 'this fire once burned that thing', which also indicates that the past fire and the fire of the present time belong to one and the same continuum of fire; thus one says, 'this fire once burned that thing'.