Moo on Obedience in Romans 6:1–14
These comments come in section III.B.2, as he summarizes 6:1–14 to set up his discussion of 15–23:
[Paul] makes it clear that Christians are free from the binding power of the Mosaic law while at the same time stressing that Christians are under obligation to obey their new master — God, or righteousness. Against those who would insist on the necessity of the law as a force to curb and restrain sin, Paul proclaims the release of Christians from the power of the law as a necessary step in overthrowing the reign of sin (vv. 14–15; see 7:1–6). And against those who would pervert this new freedom into an excuse for sinning, Paul insists that even “under grace” there are obligations of obedience that must be taken seriously. For, as Paul makes clear, there is no such thing as human autonomy, a freedom from all outside powers and influences. Either people are under the power of sin, or they are under the power of God. The question is not, then, whether one will have a master, but which master one will serve. Serving sin, Paul shows, leads to death; serving God, to life.
 See Nygren. Schreiner, however, resists this line of interpretation, arguing that no longer being “under the law” does not entail freedom from Mosaic commandments.
 In many writings on the subject, J. Barclay has emphasized the obligation that is the natural response to grace in the context of the Greco-Roman understanding of gift and obligation; see, on this text, “Under Grace,” 59–76.
The Letter to the Romans. (Second Edition, pp. 422–423).
For a list of all of my posts on Douglas Moo’s commentary on Romans, see here.