The realization of all dharmas depends upon the manas

Sentient beings all take the functions and activities of the five aggregates (pañcaskandha) as self, and especially take the feelings and experiences of the six consciousnesses of the aggregate of consciousness (vijñāna) as "self" and "what belongs to self." They cling to their own feelings and experiences, and for this they create all kinds of wholesome and unwholesome karmic actions, even not hesitating to commit unwholesome deeds. Because of these karmic actions, they sink through birth and death and suffer retributive results. Where do the feelings and experiences of the six consciousnesses come from? They arise after the faculties and sense-objects make contact. Afterwards, the manas takes these feelings as self and grasps them, creating the ignorant karma of craving and attachment. To free oneself from birth and death, one must engage in contemplative practice (vipaśyanā-caryā) on the illusory, unreal nature of the feelings of the six consciousnesses—their nature of suffering, their emptiness (śūnyatā), and their non-self nature. Knowing that feelings are empty and illusory, unreal, and no longer paying attention to them, the mind gradually becomes empty; then one can eliminate the self-view (ātma-dṛṣṭi), no longer grasp at feelings, and the afflictions of greed, hatred, and delusion will be diluted and eliminated, so that one no longer creates ignorant and unwholesome karma. Being able to contemplate feelings as empty is an extremely important matter. The five aggregates are not self, and feelings are also not self—this is a very important conceptual understanding. 

The feelings of the six consciousnesses are easy to observe, but the hidden feelings of the manas behind them are extremely important and crucial. Because the manas has feeling, there are the afflictions of greed, hatred, and delusion; because it grasps at feelings, it drives the six consciousnesses to create karmic actions. The manas regards all dharmas as "mine," all belonging to "me," and takes the mind consciousness as "my function." Therefore, the elimination of self-view means eliminating the manas's self-view, and realizing enlightenment also requires the manas to realize the eighth consciousness, the tathāgatagarbha. Thus, the realization of all dharmas lies entirely with the manas, not with the mind consciousness. Through contemplative practice that is truthful and in accord with principle, the more one practices contemplation, the more one feels that the most fundamental cultivation and realization rests upon the manas. The manas is the key to becoming a Buddha and is also the master of the cycle of birth and death. When the manas has been successfully cultivated through immersion, one attains liberation and accomplishes the Buddha Way.

Through investigative inquiry and deliberation (manana), once the manas realizes the Dharma, it will overturn its former mental engagement that was not in accord with reality; its mental activities change, it no longer grasps at the five aggregates, and one attains initial liberation—this is the key to cultivation. Why is it that some people, after studying a great deal of theory, all feel that the five aggregates are not self, that they are empty and illusory, yet they still create defiled karmic actions for the sake of the body of the five aggregates, without the slightest change in their mental activities? Because those feelings are merely feelings of intellectual understanding by the mind consciousness, which do not count at all. If the manas has not realized it through direct verification, it will continue as before to recognize and take up the five aggregates, following along with the afflictions of its own mind to create karma. Therefore, all such feelings are unreliable; for any dharma, only when the manas realizes it does it count.

The manas also constantly takes the various merits of the tathāgatagarbha as its own, taking all dharmas produced by the tathāgatagarbha as self and what belongs to self, not knowing that all dharmas are illusory manifestations of the tathāgatagarbha, and not knowing that even itself is a manifestation projected by the tathāgatagarbha. This is why it creates ignorant karmic actions. Studying the Buddhadharma means first letting the mind consciousness know theoretically that these dharmas are not self, and knowing the reality of the tathāgatagarbha; then one immerses and permeates the manas, letting the manas deliberate and realize the tathāgatagarbha within all dharmas, realizing that all dharmas are neither self nor what belongs to self. 

All dharmas are manifested by the tathāgatagarbha; none of them belongs to the manas—they are all the functions and activities of the tathāgatagarbha. Only after the manas realizes this principle will its mind become empty, and only then can it cease to grasp at the self of the five aggregates. In this way, one can not only eliminate the self-grasping but also eliminate the grasping at dharmas. When the grasping at dharmas is completely eliminated, one becomes a Buddha in the ultimate sense. Therefore, the key to cultivation lies entirely in the manas. Ignorance belongs to the manas; eliminating ignorance means eliminating the manas's ignorance. Eliminating afflictions likewise means eliminating the manas's afflictions. Attaining liberation means letting the manas attain liberation. When the manas no longer grasps at any dharma, there is no bondage—this is liberation. Who is it that becomes a Buddha? Since the six consciousnesses cease and perish in every single life, the six consciousnesses cannot become a Buddha; it is the manas that becomes a Buddha. The tathāgatagarbha also does not become a Buddha. But at the ultimate level of principle, even the manas does not become a Buddha. When the day of buddhahood arrives, one will know: there is no Buddha to be attained—only then can one become a Buddha in the ultimate sense.