The mind, will and emotions of an individual
Soul, is in part, like ego. It has a tendency toward a selfish attitude - to win from a position of authority, or simple brute strength. Unless it comes under the authority of the spirit, soul can be lost or killed.
"Do not be afraid of those who kill the body but cannot kill the soul. Rather, be afraid of the One who can destroy both soul and body in hell."
"What good will it be for someone to gain the whole world, yet forfeit their soul? Or what can anyone give in exchange for their soul?"
Do not conform to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God’s will is—his good, pleasing and perfect will.