Romans 6:18 (NIV)
You have been set free from sin and have become slaves to righteousness.
This is an interesting idea, that we are all slaves to something. Salvation depicts a rescue of one in bondage. The assumption is that the rescued person becomes a freed person. But Paul here in chapter six of Romans shows that the reality is actually a transfer of ownership, from the one master, sin, to the other master, righteousness. What does it mean to be a slave of sin? It means being always bound to sin, unable to do what is right. All right then, what does it mean to be a slave of righteousness? It means not being free to sin but free to do what is right.
The rebellious teenager who wants to be free from the shackles of schoolwork abandons his education and drops out of school. He thinks he is now free but what happens? His ability to work is limited to only those jobs suitable for a high-school dropout. What then about the compliant teenager who limits himself to hard work and study and even continues this constrained course through college? Having finished his slavery to school, he has a world of opportunity available to him.
Being a servant of righteousness is true liberty.
John 8:36 (NIV)
So if the Son sets you free, you will be free indeed.