俱舍論記 18.183

18.183

「不可數習至此無果故」者，答。謂此無為不可數習令增長故，不名應習。又習為果，此無為法無有果故，不名應習。又《正理》云「然勸以涅槃置在心中者，教有情類令趣涅槃，勸令數現起緣涅槃善智，故作是言，非謂應習。」

Regarding "Because it cannot be repeatedly cultivated [...] because it has no fruit": this is the answer. That is to say, because this asaṃskṛta [phenomenon] cannot be repeatedly cultivated so as to cause it to increase, it is not called "to be cultivated." Furthermore, cultivation is for the sake of a fruit; because this asaṃskṛta phenomenon has no fruit, it is not called "to be cultivated." Moreover, the Nyāyānusāra says: "However, as for encouraging one to place nirvāṇa in one's mind, that is to instruct sentient beings to turn toward nirvāṇa, encouraging them to repeatedly generate wholesome knowledge having nirvāṇa as its object; it is for this reason that such a statement was made, not that [nirvāṇa itself] is to be cultivated."