When studying the Dharma, the mind consciousness should investigate together with the manas within meditative concentration

No matter how many dharmas the mind consciousness knows, if the manas does not know, it will harbor doubt, and the mind will not feel grounded and settled. In order to resolve the manas's doubt and prevent the manas from doubting again, one should not let the mind consciousness know alone; the two consciousnesses should investigate together. After personal realization through direct contact, both consciousnesses will know, and there will be no more doubt. To eliminate doubt and give rise to faith, one must not only eliminate the mind consciousness's doubt, but even more so eliminate the manas's doubt.

Therefore, in studying the Dharma, the mind consciousness should try not to speculate; instead, it should investigate together with the manas within meditative concentration (samādhi). The doubt of the mind consciousness is shallow, while the doubt of the manas is deep. The deeper the doubt, the greater the relief once it is resolved, the greater the wisdom, and the more the body and mind can be transformed.