This chapter is a transition in Romans. Up to this point, Paul has been telling us all the great things God has given us. Today he begins to talk about practical things we can do in response. The biggest is right at the beginning: give God complete control of your life. Being a sacrifice means that you have given up all of yourself. Being a living sacrifice means that you get to choose. No one chooses to give God control all the time, but it always makes sense given that God always loves us and His Spirit is always in us.