成唯識論述記 3.127

3.127

然以唯識轉變次第，先行後境，次略答中，依頌而牒，下解釋中，從後向前，依問而解，所以者何？本頌先後法相求故，心依境因方得起故，長行先後意趣求故，其境要是識所變故。謂本頌中先不可知之所緣，後不可知之行相，明解法相，頌文穩便故，不可知為初，所緣、行相隨後，一不可知通境、行故。長行之中，一切諸法有心、有境，行相是識之見分故，先明行相；由心變境，次說所緣；約見及相而辨細、麁，後解不可知義，故有別也。

However, in terms of the order of transformation in consciousness-only, mental activity precedes the external object; then in the brief answer, it follows the verse in taking up the terms; below, in the explanation, it proceeds from back to front, explaining according to the question. Why is this so? The root verse follows the order in pursuit of the characteristics of phenomena, because the mind can arise only by relying on the cause of the object; the prose follows its order in pursuit of the intended meaning, because the object must be transformed by consciousness. That is, in the root verse, first comes the unknowable cognitive object, and then the unknowable cognitive aspect, clearly explaining the characteristics of phenomena; for the convenience of the verse's phrasing, 'unknowable' is at the beginning, with cognitive object and cognitive aspect following after, because the single word 'unknowable' applies to both object and activity. In the prose, among all phenomena there are mind and object, and since the cognitive aspect is the seeing aspect of consciousness, it explains the cognitive aspect first; because the mind transforms the object, it speaks of the cognitive object next; and by examining the fine and coarse in terms of the seeing aspect and the object aspect, it explains the meaning of 'unknowable' last; hence there is a difference.