Paul seems to be addressing a number of reasons or excuses he had encountered for people to ‘keep on sinning’ after their sins had been forgiven. This is a common issue, because we love our sin. Consider overeating as an example. We do not like the consequences of it, but the eating itself is something we love. We are addicted, enslaved. Think about that for a minute. Is there some sin in your life that you can always find an excuse to continue?
This is what Paul was trying to address. Because of what God has done for us through Jesus Christ, we now have the freedom to choose whether or not we will be enslaved to sin. Are there things in your life that are enslaving you? That seem to have power over you?
Romans 6:12-14 NLT
Do not let sin control the way you live; do not give in to sinful desires.  Do not let any part of your body become an instrument of evil to serve sin. Instead, give yourselves completely to God, for you were dead, but now you have new life. So use your whole body as an instrument to do what is right for the glory of God.  Sin is no longer your master, for you no longer live under the requirements of the law. Instead, you live under the freedom of God’s grace.