The Body, the dwelling or as I like to refer to it as the HOUSE. As we all know, you cannot have the other 2 without a place to house them. Think of it like going out and buying furniture with nowhere to put it. So we must protect and keep the house up, or it will surely get repossessed by the grim reaper!
The Mind. Housed inside of the body, must be kept pure and positive most of the time. It would be impossible to be that way all the time. For the most part 80% of the time. Your thoughts are processed here, and your ability to sort and prioritize feelings, thoughts, emotions, etc. So if your body and mind are in sync, you will always have balance.
The Soul. This being the most complex of them all. Some connect a healthy soul to religion and spirituality. However, my take is "a healthy body and mind = a healthy soul". Your soul is believe to be the root of your inner being. It can be quenched with positive or negative energy. You hear people say "He has an old soul", or "She has a good soul" even "his soul is evil". If the soul is fed evil, it will harbor evil ways. If it is fed good, it will only know to act out the same. Thus, spiritualist and evangelist recommend the Holy Bible. ITS NOT REFERRED TO AS THE "GOOD BOOK" FOR NOTHING.