There are two ways of interpreting the question, "What's a body to do?":
I talked on Sunday about the mine fire in Centralia, Pennsylvania. It's a place where the ground is literally shifting, where people can't plan a community or nor build a home. The community's initial efforts to mitigate the fire were “band-aid” (piecemeal) solutions. The North American Church in the recent past has responded to many cultural changes in the same way: putting our fires and filling in sinkholes without recognizing they are all connected to the fire underground. What is needed is to search scripture for a solid foundation from which to respond to the many changes that the wider culture is implementing-- not just negative reactions but a positive vision of what it means to be an embodied human being in relationship with our Creator God.
Tim Keller talks about the loss of a “sacred order” (present in all human cultures, not just the Christian West) which means that there is no longer a consensus on what it means to be human. So what does it mean to be embodied? What purpose, if any, do our physical bodies have? What conception of the body does the Bible actually give us? This is our task together, to allow the Spirit to speak to us about a biblical theology of the body.
Therefore, I urge you, brothers and sisters, in view of God’s mercy, to offer your bodies as a living sacrifice, holy and pleasing to God—this is your true and proper worship. (Romans 12:1 NIV)
Therefore I urge you, brothers and sisters, by the mercies of God, to present your bodies as a living and holy sacrifice, acceptable to God, which is your spiritual service of worship. (Romans 12:1 NASB)
In Greek, the word used here for 'bodies' is soma, the integrated person, the whole organism, not any one part but all of oneself (versus the word sarx , or 'flesh', used by Paul elsewhere in Romans and other epistles to describe humans operating without the Holy Spirit). The word logikos-- true and proper/spiritual service-- means following from, according to sound argument, also pertaining to humanity’s philosophical abilities to touch the divine reality.
Understanding these words, we see that Paul is inviting his audience into a kind of discipleship that is not simply mental contemplation (as some Greek philosophies taught), but rather the giving of one’s whole self to God and others, as in Jesus’ Great Commandment to “love the Lord your God with all your heart, mind, soul, and strength." This includes our physical bodies. Paul is also inviting us to a discipleship that is both reasonable (in the sense that it logically follows from the great mercy God has shown to us) and spiritual (in the sense that our bodies are intimately connected with our minds/spirits). In the worldview of the Old Testament/Jewish diaspora, there was no spirituality that didn’t include what we do in the material world with our physical bodies– to use your physical body is connected to the spiritual realities and relationship with God.
Paul is speaking in opposition to the Greco-Roman ideas of a soul “trapped” in a body. Rather, God wants our whole selves, including our bodies, to be oriented to Him in worship. Using our bodies for His glory is also spiritual– it allows for communion with the divine. Notice the metaphorical use of the sacrificial imagery, tying the forms of Israel’s historical worship to their fulfillment as Jesus’ followers; the Old Testament picture of worship (dead animals sacrificed for human sin) is transformed into “living sacrifices”– human lives lived fully in the worship of God.