For if you live after the flesh, you shall die: but if you through the Spirit do put to death the deeds of the body, you shall live.
All Commentaries on Romans 8:13 Go To Romans 8
John Chrysostom
AD 407
You can see from this that Paul is not talking about the essence of the body but about the evil deeds which it does. For if we stop doing evil deeds, then our physical bodies will live.