The following teaching was taken from a board in Wat Baan Taad:
When discussion the khandas, I use the simile of a computer. The body is like the hardware, and it must be there. The 4 nama-khandas are like the software, and the computer is useless without it. You must have the software. The citta is like a person who uses the computer. The person using the computer can make it do good things or bad things, or stupid things. He can push it about all over the place. It is similar with our khandas. The citta is the one which plays with them and pushes them around. It's their master. Ad the khandas are all used for the citta's sake- for developing whatever it wants. If the citta were pure, it wouldn't matter. But it's not pure. It has kilesas in it. And it is the citta with kilesas that causes all the trouble. If the kilesas were in the body instead of being in the citta, hen the body dies the kilesas would all disappear- there would be none left. But the fact is, the kilesas are in the citta, which does not die. So the kilesas carry on and go to the next life. Because of that, we come back again and again.
So it is essential to understand that the kilesas are in the citta and not in the khandas. But the khandas take n those aspects of the kilesas which the citta makes them take on. For instance, anger. Anger starts off in the citta. This triggers a response in the khandas. First of all, consciousness become aware of it, and memories associated with it begin to arise. Then the thinking process builds it up and causes anger to increase. Then feelings arise. These feelings came from the anger inside the citta. This brings us back to the citta and the kilesas. The kilesas are the things that push us around all the time. And the whole purpose of the Buddha-Dhamma and the Buddha Sasana is to get rid of those kilesas.