"By using this imagery of a transfer of realms, or 'dominion,' with its association of power and rulership, Paul makes clear that the new status enjoyed by the believer (justification) brings with it a new influence and power that both has led and must lead to a new way of life (sanctification).
"This 'must' is very important. For, as decisive and final as is this transfer into a new realm, it would be a bad misinterpretation of Paul to think that the believer is thereby removed from all contact or influence with the old realm of sin. While belonging to a new realm, the believer brings with him into it many of the impulses, habits, and tendencies of the old life, a constant threat to putting into actual practice the realities of our new realm status. It is this 'eschatological reservation'--the fact that not until the resurrection and transformation of the body will the believer be severed from all contact with the old Adamic dominion--that explains the 'indicative/imperative' combinations that are so characteristic of these chapters: 'sin will not rule over you'/'do not let sin reign' (6:13-14); 'you are not in the flesh'/'do not live according to the flesh' (8:9, 12)."
--Douglas Moo, The Epistle to the Romans, New International Commentary on the New Testament (Grand Rapids, MI: Eerdmans, 1996), 352.
