Having spent eleven chapters speaking about what God has done for us, Apostle Paul now tells us what "reasonable service" we can do in response to God for what He has done. We should become "Living Sacrifices" by allowing God's faith to transform our lives. In particular, we are to allow God to use our bodies to express and prove to others what God has done for us in the Spirit, by expressing those things through our bodies. God has conformed our Spirit to that of Christ image and all he ask of us to transform that Spiritual conformity into being visible to others through our physical lives as a testimony of God's Gracious work to us and all of mankind who will humbly submit to Him in faith.

Romans 12:1-2 I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. 2 And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.