If our lives are not in tune with God, as they should be, our souls act as bones and joints which form a shell around the marrow of the spirits within them. But he that is joined unto the Lord is one spirit. So, when the soul is hardened against God it is like a barrier surrounding the spirit and hindering God's Spirit within the human spirit of a born again believer to be blockaded from flowing outward. When it is turned within to the things of God that can only be related to by using the human spirit, as opposed to the flesh, we see the need of breaking self life. The hindering soul must be broken.
Faith is a work of the spirit.
Works originate with the flesh. This allows the Spirit of God, which is one with our human spirits, to flow outward and work through us. He is within us in order to be able to use us. But he cannot use us if He is not allowed to manifest out through our lives. And a fleshly minded soul is like a barrier that hinders Him from coming through the vehicle of the soul and out to minister to the world.