俱舍論頌疏論本 21.89

21.89

釋曰：初句答第一問，下三句答第二問。諸惑無再斷者，諸惑頓斷，若更不退，必無後時再斷惑義。

Explanation: The first line answers the first question, and the lower three lines answer the second question. Regarding "the defilements are not abandoned again": defilements are abandoned once and for all; if one does not fall back, there is never any sense in which defilements are abandoned a second time at a later occasion.