俱舍論疏 30.72

30.72

論「故說今我至曾燒彼事」，論主述正義也。如人將一炬火，先燒其草、後燒其木。雖剎那滅，是一相續，得說此燒木火曾燒於草，非謂前後火體不別。世尊今我昔師義，亦准此顯昔與今是一相續，非前不滅。

On the Śāstra's: "Therefore, to say that the present 'I' ... previously burned that matter": The author of the Śāstra sets forth the correct view. Just as a person takes a single torch, first burning grass with it and later burning wood with it—although it perishes from moment to moment, it is a single continuum, and one can say that this fire burning the wood had previously burned the grass, not that the substance of the earlier and later fires are not distinct. The meaning of the World-Honoured One's "I at present was the Teacher in the past" is also shown in accordance with this: the past and the present are a single continuum, not that the former did not perish.