What is the purpose of studying Buddhist theory?

The purpose of studying the Dharma should be to attain liberation from the bondage of the five aggregates (pañca-skandha), liberation from the bondage of all kinds of dharmas. Who is liberated? It is the sixth and seventh consciousnesses that are liberated; it is the first seven consciousnesses that are liberated. Because the first seven consciousnesses are bound by the self of the five aggregates, possessing self-grasping, and are bound by dharmas, possessing dharma-grasping, the purpose of studying the Dharma and its theories is to enable the seven consciousnesses to fully and completely recognize the illusory unreality of the five aggregates and the fault of birth-and-death that they cling to, and to fully and completely recognize the illusory unreality of dharmas and their bondage, thereby breaking free from bondage and attaining liberation. If studying the Dharma is merely to acquire theoretical knowledge, so that the mind consciousness can hang it on its lips and flaunt and show it off everywhere to display erudition, then the mind has been misused—this is another kind of grasping, still ignorance and bondage. 

Many people who study the tathāgatagarbha dharma, no matter what they discuss, force everything onto the tathāgatagarbha, never touching upon how the seven consciousnesses and the five aggregates should be cultivated and studied so as to be transformed and to eliminate the bondage of ignorance and afflictions. They never know how to compare against the pure mental conduct of the tathāgatagarbha, how to repent and eliminate the defiled mental conduct of the seven consciousnesses and the five aggregates. They split the principle of the tathāgatagarbha's purity and the five aggregates and seven consciousnesses into two separate pieces; the principle of the tathāgatagarbha merely hangs on their lips, while the mental conduct of the seven consciousnesses remains as before. They are keen on pursuing theory, do not devote themselves to introspecting the ignorance and afflictions of their own minds, and even less do they contemplate how to govern the defilements within. Such a way of studying the Dharma has nothing to do with practice; moreover, it will increase the mind of pride—generating arrogance from knowing much, looking down haughtily on others—with the result that ignorance and afflictions are further increased. What is the point of that? 

We should all clearly understand that no matter what the tathāgatagarbha is like, it does not represent the mental conduct of the seven consciousnesses. The tathāgatagarbha is the emperor, while you, the seven consciousnesses and five aggregates, are still lowly people, commoners in plain clothes, impoverished people; none can substitute for the other. Only by studying the purity and selflessness of the tathāgatagarbha, removing defilements, and acquiring merit and wisdom can you rise step by step. Only when your merit, wisdom, and conduct become on a par with the tathāgatagarbha can you, like the tathāgatagarbha, become an emperor, supremely noble. Whoever does not contemplate their own mind, does not repent of the afflictions in their own mind, does not wish to change themselves, whose body and mind undergo no change whatsoever, and who does not actually set about cultivating precepts, meditative concentration (samādhi), and wisdom—none of this can be called practice; it has nothing to do with cultivating the Path, and it would already be quite good if the theories they studied did not become a burden to themselves. So please do not, on the one hand, utter "tathāgatagarbha" with every breath while, on the other hand, being laden with the afflictions of greed, anger, and delusion without knowing it.