俱舍論記 25.48

25.48

「阿毘達磨至是名由教」者，經部復引論教，證無學人不退果也。論具三因，惑方得起；應果起惑不具三因，明知不退。若謂彼據具足三因生煩惱說，復有何惑法因不具足生？若謂無學退起煩惱因不具生，惑既已斷，如何得起？此即以理徵責必須具因。又解：若謂彼據具三因生說，復更有何法因不具足生，如染心、心所法必具五因生，無不具五而得生者。三因起惑應知亦爾。此即責例，是名由教。

"Abhidharma […] this is called 'by scripture'": the Sautrāntika further cites the teaching of the treatises to prove that the aśaikṣa does not fall away from the fruit. The treatise states that only when the three causes are complete can defilement arise; an arhat giving rise to defilement would not possess the three causes, so it is clearly known that they do not fall away. If it is said that that is stated with respect to the arising of defilement with the three causes complete, then what defiled dharma could arise without the causes being complete? If it is said that when an aśaikṣa falls away and defilement arises, it arises without the causes being complete, since the defilement has already been severed, how could it arise? This is examining and demanding by reason that the causes must be complete. Another explanation: if it is said that that is stated with respect to arising with the three causes complete, what other dharma could arise without the causes being complete? For instance, defiled minds and mental factors must arise with the five causes complete; none can arise without the five being complete. The arising of defilement through the three causes should be known to be the same. This is demanding by analogy; this is called 'by scripture'.