Think about laws for a minute.
To help with your thinking, I'm going to say there are two types of laws that serve two different purposes.
There are "active laws" which tell us what we are required to do and what we are forbidden to do. Rewards or punishments follow.
There are also "inactive laws" which remind us what is expected. These are laws that used to be "active" but have changed so that obedience is no longer enforced. But the desire of the lawgiver is still perfectly clear.
Here's an example.
It used to be a law in our house that the children were in bed with lights out by 9:00 pm. If they did that, all was well. If they did not, there were consequences. Now that those "children" are 16 and 19, the 9-o'clock-rule is no longer in force. It has gone from being an active law to an inactive law.
They still understand, however, that although I don't stand next to their beds at 8:59 with a stick in one hand and a carrot in the other, my desire that they get a decent night's sleep has not changed. I just no longer force them to do it. They are now free from that law, and they make their own choices.
Now, here's why we're thinking about laws.
The New Testament makes a big deal about active and inactive laws. It never actually refers to them that way. But that's the gist.
Normally, this concept is couched instead in terms of freedom - specifically, freedom from the Law - and it refers exclusively to those who are in Christ.
For the Christian, our acceptance by God is not based on anything we do or don't do. For the Christian, all laws have been deactivated.
It's with this understanding that we can make sense of what Paul says in Romans 6:15-16.
In the previous verses, Paul went to great lengths to convince his readers that we are in fact completely free from law. Once he's made that case as clear as possible, he then asks an obvious question: If we really aren't required to obey any rules anymore, what are are going to do? Obey them anyway?
What then? Shall we sin because we are not under law but under grace?
Maybe it's just my imagination, but I bet there were plenty of people reading that letter who hoped the next sentence would be, "Heck yes we will! We're free! Let's go out and sin, sin, sin!!!"
But it wasn't. Instead, Paul answered his own question like this:
(The phrase translated "Certainly not!" in my Bible has a little more pinch in the old King James, which renders it, "God forbid!". However you translate it, it comes from two Greek words that mean essentially, "May such a thing never be".)
At this point my imaginary reader would ask the next obvious question: "Well, why not, Paul? Seriously! If we can do whatever we want, why wouldn't we?!"
Paul's answer to this is simple. And a little frightening. He writes:
Do you not know that to whom you present yourselves as slaves to obey, you are that one’s slaves. . . ?
There are only two options here.
By your actions, words, thoughts, choices you either present your saved and forgiven self to obedience/righteousness/God or to sin/death/Satan.
That's it. There are no neutral positions.
And, there is no coercion. Because we're free.
The "problem" is, as free men and women we have the responsibility to freely make good choices. (And that's hard. It's so much easier to make good choices when you are forced to! Or is that just me?)
God is still the God of righteousness, goodness, and love.
Satan is still the god of disobedience, evil, and selfishness.
So, will you freely choose to be on God's side? Or will you equally freely stand with Satan?
Remember this: The way we live our Christian lives is not about obeying rules or being good.
It is all about choosing sides.