Human beings have two problems that are related. First, we are mortal. We will die.... as the adage goes, "Not one of us will get out of life alive." Second, we are flesh and for Paul that does not mean physical flesh covering bones, but living life that is not in character with God's will and desires for human beings. For Paul, life in the Spirit means that flesh and blood human beings can live a life that is not according to the flesh.
The first thing Paul wants to assert in this passage is that those who "are in Christ Jesus" are not condemned. The war within the unconverted soul in chapter 7 can be won, but by only divine intervention. Just who is it that can save us from this body of death (7:24). As Paul has already addressed justifying grace in chapters 4 and 5, and prevenient grace in chapter 7, here in chapter eight he speaks of sanctifying grace, the process by which the Holy Spirit molds and shapes our entire lives: body, mind, and spirit to conform to the ways and will of God. It is the process of the restoration of God's cracked image in us.
In that transforming grace, we who are made of blood and bone are not resigned to live by that which is opposed to God. We walk "according to the Spirit." In Jesus Christ through the power of the Holy Spirit, God gives life to our mortal bodies in the here and now. Eternity does not begin after we take our last breath, but right now in the present we begin our participation in that eternity. And that means a new way of life. We are not consigned to living for the flesh while in these mortal bodies. To believe so is to reject the life-giving power of the Holy Spirit and to remain in the pre-converted state of perpetual self-focus. But it is God's Spirit that is capable of fixing our attention on the divine. As we do so, we lose our self-conscious concern and instead put our gaze on God-- the only one who can deliver us. As Jesus says in another context, "What is impossible for mortals is not impossible for God" (Luke 18:17). Alan Brehm writes,
We all have the choice to close in on ourselves, on our own needs and wants and desires, or to open ourselves to the joy and love and life that is all around us. But it takes a leap of faith to open ourselves to life—we have to take the risk of letting go all our selfish pursuits and opening ourselves to the wonderful and unpredictable Spirit that is flowing so freely and so full of life all around us.In these verses, we deal with more than individual acts or lone types of behavior, but an orientation toward life that only God can give. God can work his sanctifying grace in our lives only with the mindset of the Spirit; and it is that orientation that engenders behavior that is not according to the flesh, but according to the Spirit that gives life to our mortal bodies in the present.
Just as the Spirit raised Jesus Christ from the dead in this present world, so that same Spirit gives life to those who follow Jesus in this present world.
We are in Christ. We have the Spirit. Let us now become what we are.