What does the manas rely on to arouse manasikāra toward dharmas?

The manas' attention (manaskāra) operates in several ways: first, relying on its habitual tendencies, it habitually attends to certain dharmas that frequently appear and are familiar, easily directing attention toward them; second, the manas may direct attention aimlessly, which is caused by its habitual tendencies of distraction and seeking; third, the manas easily gives rise to attention toward dharmas it finds interesting; fourth, the manas easily gives rise to attention toward major and important dharmas; fifth, the manas gives rise to attention because of craving and attachment to certain dharmas; sixth, the manas gives rise to attention due to afflictions such as anger and resentment; seventh, the manas gives rise to attention toward dharmas it needs; eighth, the manas easily attends to dharmas that appear suddenly, and so on—the examples are too numerous to list exhaustively.

After the manas directs attention, perhaps the mental factors of contact (sparśa), feeling (vedanā), perception (saṃjñā), and volition (cetanā) do not come forth and operate; perhaps there is no volition mental factor, and the manas does not decide what to do; perhaps the perception mental factor does not come forth and operate, and the manas does not grasp at the dharmas it takes as object; perhaps the feeling mental factor does not come forth and operate, and the manas does not wish to feel, having no interest in the object dharma. At the very beginning, when the preceding mental factor does not appear, there is no need for the subsequent mental factor to appear either.

How the Manas Directs Attention to Bring About Its Own Cessation

When an arhat liberated by wisdom (prajñā-vimukta) is at the end of life, the manas no longer craves the three realms, no longer directs attention, no longer chooses to see dharmas, has no desire to see dharmas, and has no desire to engage in activity. When the five universal mental factors do not manifest, the manas must cease. Therefore, when the manas does not direct attention to contact, feeling, perception, and volition, the tathāgatagarbha does not cooperate in generating dharmas. When the manas no longer has desire and mindfulness toward the three realms, it will certainly not direct attention to contact, feeling, perception, and volition; consciousness can no longer operate, and the functions of the five aggregates do not arise—thus the manas ceases. As long as the manas has mental thoughts and desires, and has the tendency to seek after the dharmas of the three realms, the five universal mental factors will continue to operate; the manas cannot cease, the five aggregates and eighteen realms will continue to be born, and sentient beings will undergo birth and death in the three realms without interruption.