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.
I believe it is reasonable for God to expect us to live our lives for Him. It’s not that we are working off our salvation, but it demonstrates an appreciation for the love God demonstrated to us by sending His Son to die for us.
When we are told not to be conformed to this world, that’s because the it is the worst thing for us to do. Instead, we are encouraged to be transformed by renewing our mind from our old way of thinking, to a new way of thinking and living. When we think (and act) the way the way God thinks, we demonstrate to the world that God’s will is good, and it is right.
We can’t do this on our own…that’s why God gives us His Holy Spirit to lead and guide us. And the new mind we have is regenerated by Him. That’s why we are told in 1 Corinthians 2:16 that we have the mind of Christ. Let’s use it as we live our lives separated from the world, but separated TO God.