What use is mind consciousness to manas?

The mind consciousness, the five sense consciousnesses, and the five aggregates are all tools that the manas must use. Without these tools, the manas would be powerless in the world on its own; it needs the six consciousnesses and the five aggregates to serve it, using the six consciousnesses and the five aggregates to greedily grasp all dharmas in the world. Without the six consciousnesses and the five aggregates, the manas would be helpless.

Therefore, the manas can know many dharmas, but these dharmas must be processed by the mind consciousness. For example, when ghosts or spirits appear nearby, the manas feels quite frightened, fearing they may threaten itself, but it cannot deal with ghosts and spirits itself, nor can it evade them on its own. So, while the hairs on the body stand on end, it alerts the mind consciousness to this matter. The mind consciousness then wonders: What exactly is going on? Why do I feel afraid? Why does the surroundings feel eerie, as if something is happening? When the mind consciousness is sharp and thinks it over, it may realize that there are ghosts or spirits nearby, and then it finds a way to avoid them. In this way, the manas achieves its purpose.

Therefore, although the manas has the capacity of knowing, matters still need to be handled by the mind consciousness and the five aggregates. After the manas realizes the dharma, the pure bodily, verbal, and mental actions need to be carried out by the mind consciousness and the five aggregates; thus, the pure bodily, verbal, and mental actions of the six consciousnesses manifest the purity of the manas. However, after cultivating to a considerably high level, when the four dhyānas and eight samādhis have been cultivated and immeasurable supernatural powers and powers of the Path are fully possessed, the manas can substitute for the six consciousnesses. At that point, the six consciousnesses need not emerge at all; all matters are handled by the manas itself, which is extremely swift and convenient. Therefore, the functions and status of the mind consciousness cannot compare with those of the manas; the relationship between the two is forever that of master and servant. The master needs the servant to take care of trivial affairs, but when the master's capabilities are great, with everything running on modernized programs, the servant is no longer needed—the master can handle everything well and skillfully by itself.