大乘起信論義記 3.77

3.77

問中言若心滅云何相續者，若境界滅時心體亦滅者，無明三細既其未盡，心體已亡，更依何法而得相續？此疑相應心。若相續云何究竟滅者，若言以心體不滅，令無明得相續者，心體既其不滅，無明則常相續，云何治道得究竟滅也。此疑不相應心。答中雙答此二也。

In the question, the words 'If the mind ceases, how can there be continuity?': if when perceptual objects cease the substance of the mind also ceases, then since the avidyā of the three subtle marks is not yet exhausted while the substance of the mind has already perished, relying on what phenomenon could there still be continuity? This doubts the conjoined mind. 'If there is continuity, how can one speak of ultimate cessation?': if one says that because the substance of the mind does not cease, it causes avidyā to continue, then since the substance of the mind does not cease, avidyā would continue permanently; how could the path of the antidote attain ultimate cessation? This doubts the unconjoined mind. In the answer, both are answered together.