After an Arhat Attains Nirvāṇa, Karmic Seeds Still Remain in the Tathāgatagarbha

Because arhats have eliminated self-grasping, they no longer grasp at the worldly dharmas of the three realms; with fundamental ignorance (一念无明) extinguished, when their conditions with the three realms come to an end, they enter nirvāṇa and will not be reborn within the three realms. As for the claim that arhats will in the future emerge from nirvāṇa, that is because they have cultivated and permeated themselves with the Mahāyāna Dharma, and the seeds of the Mahāyāna Dharma have ripened in their conditions—not because the seeds of the dharmas of the three realms have ripened. Arhats will no longer be born in the three realms due to the seeds of the dharmas of the three realms.

Then, at the time an arhat enters nirvāṇa, do the seeds of the dharmas of the three realms still exist? A seed is the aspect of generative capacity; where there is a seed, it must necessarily manifest. Yet an arhat no longer manifests the seeds of the three realms—so where have the seeds of the three realms gone?

Seeds are formed through ignorance and power of aspiration. An arhat's fundamental ignorance has been extinguished, so no seeds of the three realms will be formed again; and since an arhat has no power of aspiration, neither will seeds of the three realms be formed. According to the teaching of the twelve links of dependent origination, ignorance conditions volitional formations (avidyā-pratyayāḥ saṃskārāḥ), and these formations are all the bodily, verbal, and mental actions and so forth within the three realms. Without ignorance, the formations of the three realms must all cease, and there will be no further birth of the five aggregates (pañcaskandha) body. The Mahāyāna Dharma that arhats cultivated and permeated themselves with before entering nirvāṇa becomes seeds deposited in the mind-substance (tathāgatagarbha); their slight fondness for the Mahāyāna Dharma also becomes a seed, which can bring about the ripening of the conditions for the seeds of the Mahāyāna Dharma. The greater the fondness, the more easily the conditions ripen, and the earlier they ripen—the earlier they will emerge from the state of nirvāṇa and take rebirth again.

Before an arhat enters nirvāṇa, because the manas no longer grasps, the seeds of the Mahāyāna Dharma are stored in the USB drive (tathāgatagarbha); when they are reborn in a future life, it is the ripened seeds in the USB drive (tathāgatagarbha) that summon forth the world of the five aggregates.