All three assets create the being of all beings. The superior is the mind. Why? Because your mind is the one that controls your life.
The mind is the strongest but yet is still weak, only if you let your guard down.
But to actually make this make sense, think of these three assets as a bird. The soul and the spirit are the wings and the mind is the body. They all help one another to complete the being.
2 Corinthians 10:5
"Take every thought captive"