Retrogression and Non-retrogression in Cultivation Lie in the Manas

The deeper the meditative concentration, the more the manas can be put to use; the shallower the meditative concentration, the weaker the manas becomes. Whether one regresses or does not regress depends on the manas. When the manas earnestly and solidly investigates and deliberates on one's own, seeking the answer, once it reaches a conclusion, He becomes extremely certain and will not doubt it, for no one trusts anyone more than oneself.

Therefore, when little effort is exerted, what is realized is shallow, and doubt cannot be fully severed, making regression easy in the future. If the manas does not realize it, doubt cannot be dispelled in the slightest; it does not count as realization, cannot sever the bonds of fetters, and therefore the question of regression does not even arise. If one is investigating the tathāgatagarbha, then the question of the transformation of the basis as tathāgatagarbha (āśraya-parāvṛtti-tathāgatagarbha) likewise does not arise, because without realizing it, how can one rely on it? Without relying on it, there can be no transformation. Without advancing forward, there is no falling back. If one merely plays tricks with the mind consciousness, one will suffer greatly at the time of death—will there still be time for regret then?