Using the Tri-part Being

Now that we got through the definitions and introduction we can start on the "meat" of the book, Journey into Spirit Life. Let's begin.
Scientists have long explained to us that we use only a tiny portion of
our brain, some using less than others. The same could be said for the bodies of most men and women. Look at the athlete who has pushed his body to a more full potential. Look at the brilliant scholar who has pressed his mind toward its potential. We do not deny that man has neglected full potential of mind and body but contend that we, nonetheless, give a tremendous amount of attention to inputting knowledge into our brain or soul. We also use it to contain enormous amounts of emotion. That emotion and our knowledge of life result in reasoning and that reasoning determines our decisions or will. The body, when cooperative, then lives out that will. We contend that, if indeed we use our minds or souls at far less than their potential (and we do), we must use the spirit to even less degree of potential. Man's spirit must be the most neglected part of the tri-part being. How much time do we spend developing the spirit? For they that are after the flesh [body + soul] do mind the things of the flesh; but theythat are after the Spirit the things of the Spirit. For to be carnally minded [is] death; but to be spiritually minded [is] life and peace. -Romans 8: 5-6
We become "spiritually minded" by allowing the development of our spirit to become dominant over our flesh, our soul and body. In the perfected or matured believer, the spirit is dominant over flesh, resulting in more abundant life. Now, we are not contending that absolute perfection can be achieved in the earthly realm. We do, however, contend that believers have set their sights far too low and can achieve a much higher plane of maturity or perfection in their spirit that typically anticipated. We will sometimes refer to this maturity as perfected love. Because the carnal mind [is] enmity against God: for it is not subject to the law of God,
neither indeed can be. So then they that are in the flesh cannot please God. But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his. And if Christ [be] in you, the body [is] dead because of sin; but the Spirit [is] life because of righteousness. But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you. Therefore, brethren, we are debtors, not to the flesh, to live after the flesh. For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live. For as many as are led by the Spirit of God, they are the sons of God. -Romans 8: 7-14