These objections prove that the readers both then and now do not understand neither law or grace. They go to extremes: legalism on the one hand and do anything on the other. So as Pail defends justification he also explains sanctification.
He tell us how we can live lives of victory(Rom.6), of liberty( Rom.7) and of security(Rom.8).
He explains our relationship to the flesh, the law and the Holy Spirit.
In Romans 6, Paul gives three instructions for obtaining victory over sin. Listen these are not just hypothetical suggestions but real instructions for victory. Do you want to know them? Do you want victory over sin?