Chapter 6 reminds us, in a rather blunt fashion, that Christians should not sin. Because we’re not under law gives us no excuse to sin . . .
15What then? Are we to sin because we are not under law but under grace? By no means!
It also reminds us that we’re slaves of who or what we obey. If we obey God, we’re slaves to righteousness. If we choose to sin and live under its power, we become slaves to sin.
. . . you are slaves of the one whom you obey, either of sin, which leads to death, or of obedience, which leads to righteousness?
Then Paul sums it all up by letting us know what the consequences of our choices will be.
23For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.