What Karmic Seeds Reside in the Arhat's Eighth Consciousness Mind?

Arhats live according to conditions within Nirvana with residue, unattached to all dharmas of the world of the five aggregates, with minds empty and devoid of self. The karmic seeds of the worldly dharmas in the three realms gradually dissipate. Since there are no longer karmic seeds of the three realms, there will be no threefold world in future lives, nor will there be a five-aggregate body born within the threefold world. If the eighth consciousness of an Arhat still contains karmic seeds of the three realms, these seeds must inevitably manifest to requite karmic actions, and there would be no state of Nirvana without residue.

However, after Arhats enter Nirvana without residue, they will eventually reappear in the threefold world. This is because, prior to attaining Nirvana, all Arhats have heard the Mahayana teachings and planted seeds of the Mahayana Dharma. When these seeds mature, the eighth consciousness will emit consciousness seeds for the manas (mental faculty), giving rise to manas, entering an intermediate state body, and taking rebirth again to study the Mahayana.

Karmic seeds correspond to manas, and manas corresponds to karmic seeds. If manas does not cling to the threefold world, it cannot retain worldly karmic seeds. If there is clinging, it will continue to create wholesome and unwholesome karmas, leaving karmic seeds behind. In future lives, one will continue to take rebirth and cycle through samsara according to these karmic seeds. If manas does not cling, the six consciousnesses do not create karma, and thus there are no karmic seeds, freeing one from experiencing karmic retribution.