成唯識論了義燈 4.109

4.109

簡別境五中。問：此師第七何無欲耶？答：緣未遂境，可有欲生，此識緣我，恒遂無欲。難七緣境恒遂，不希未遂無欲俱，佛果所緣恒現前，無彼未合欲不起。答：佛果悲願度眾生，境界雖現欲無減，因中我法恒現取，無願不希非欲並。又釋如疏，餘四准此。

Regarding the exclusion among the five specific mental factors: Question: Why does this master hold that the seventh has no desire (chanda)? Answer: When taking an unattained object, desire can arise; this consciousness takes the self as object, and since it is constantly attained, there is no desire. Objection: If the seventh's object of cognition is constantly attained, so that it does not seek what is unattained and lacks desire, then in the fruition of buddhahood the perceived object is constantly present, so without an unattained object, desire would not arise. Answer: In the fruition of buddhahood, through compassionate vows beings are delivered; although the domain is ever present, desire does not diminish. In the causal stage, self and dharmas are constantly apprehended as present; having no vows and no seeking, it does not accompany desire. Another explanation is as in the commentary; the remaining four should be understood by analogy to this.