Romans 12:1, 2

I beseech you therefore, brethren, by the mercies of God, that you present your bodies a living sacrifice, holy, acceptable to God which is your reasonable service.  And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God.  

This scripture isn’t as complicated as it seems.  Our spirit with the Holy Spirit’s help and the word of God is supposed to be guiding our minds and our bodies.  The body is just a shell, and our spirit is the real us.  The renewing of the mind to the word of God builds us up on the inside.  Then our spirit full of the word of God will reign over our flesh.