Why Does Buddhism Strictly Forbid Explicitly Revealing the Hidden Meaning?

All dharmas in Buddhism that need to be realized and awakened to belong to the secret dharma. What is meant by secret dharma is that these dharmas must be personally investigated and personally verified by oneself; one should not obtain ready-made answers from others, nor use the conscious mind to guess and imagine. Because ready-made answers obtained from others, as well as answers produced by guessing and imagining, only correspond to the conscious mind—the conscious mind can easily understand and grasp them, but the manas cannot understand or grasp them. For the manas to understand and grasp, it must go through the process of investigation: the manas must personally participate in the conscious mind's deliberation and verification, understand every detail transmitted by the consciousness, grasp every piece of evidence, and carry out verification and deliberation (manana). Only when the evidence is sufficient and the manas has deliberated clearly can the manas know conclusively. If the manas does not know, there is no realization; if the manas does not realize, there is doubt; with doubt, one does not realize the truth, and there is no liberating merit and benefit.

Therefore, in Buddhism, not only is explicitly revealing the hidden meaning strictly forbidden in the Mahāyāna dharma, even in the Small Vehicle dharma it is forbidden to explicitly describe contemplative practice (vipaśyanā-caryā) in too much detail, so as to avoid the situation where the consciousness knows but the manas does not. If it is explicitly stated, the conscious mind will immediately understand it, and thus cannot investigate it; without going through investigation, the manas cannot understand it and cannot realize it. If the manas has doubt and cannot resolve it, then there is no liberating merit and benefit.

Therefore, for any dharma in Buddhism, whether of the Great Vehicle or the Small Vehicle, it must not only be realized by the conscious mind; most importantly, it must be realized by the manas. Because the manas governs body and mind, once it realizes the truth, it can accord with the truth and relax body and mind, thereby bringing about liberating merit and benefit for body and mind. The intellectual understanding of the conscious mind has no liberating merit or benefit. When the manas realizes and awakens, the body, mind, and world will undergo a transformation and obvious changes; others can see from the outside that this person's mental state has changed—relaxed and at ease, spirited and vigorous. The Chan masters of the past had the eye of the Way: when they saw a disciple who had been investigating Chan walking over to report the results of their Chan investigation, without the disciple opening their mouth, the master already knew that this person had attained the Way, because they saw that the disciple's entire spiritual demeanor and temperament had changed.

From this, it can be seen how crucial and important the manas is for realizing the dharma—it must not be overlooked. Practitioners must never be satisfied with the coarse and shallow understanding of the conscious mind while abandoning the deep personal realization of the manas, thereby forfeiting the great and true benefits of the Buddha's dharma.