Law is incapable of changing people.
It would be great if it did. That would mean all we needed to do to rid the world of evil is to make new laws.
The reality that the law is incapable of changing us doesn't mean that law is useless. It does mean that we need to understand the limitations of law, so we don't put unrealistic expectation on it.
The law does have the ability to stop some people from doing certain behaviors. It is capable of doing this because they are afraid of the punishment. In the back of their minds is that voice that is whispering, "What if I get caught?"
The restraint these people experience is not from the desire to do good, but the desire to avoid getting into trouble. They wouldn't hesitant to do evil deeds if they could be assured there would be no consequences for their actions.
Their outward appearance appears to be good, but their hearts remain dark.
Consider these snippets from the Sermon on the Mount:
"You have heard that the law of Moses says, "'Do not murder. If you commit murder, you are subject to judgment.' But I say, if you are angry with someone, you are subject to judgment! If you call someone an idiot, you are in danger of being brought before the high council. And if you curse someone, you are in danger of the fires of hell" (Matthew 5:21-22; NLT).
"You have heard that the law of Moses says, 'Do not commit adultery.' But I say, anyone who even looks at a woman with lust in his eye has already committed adultery with her in his heart" (Matthew 5:27-28; NLT).
"You have heard that the law of Moses says, 'Love your neighbor and hate you enemy.' But I say, love your enemies! Pray for those who persecute you!" (Matthew 5:43-44; NLT).
Jesus taught that what mattered more than our obedience to the law is the condition of our heart.
The law cannot fix a heart twisted by sin!
Our only hope for a true change of heart is Jesus. Our faith allows Jesus to heal our hearts and empower us to overcome the sin in our lives.
Obedience to the law is powerless to take away the consequences of sin in our lives. Law can inform us what is right and wrong, but once it has been broken, it remains broken.
What does that mean?
One thing it means is that law can't change us. The law can point us in the right direction, but it can't make us obedient. If we are interested in the transformation of lives, then we have to look at things outside of law. We need to use things like love, truth, faith, and sacrifice.
A second thing it means is that everyone is in the same boat. We have all disobeyed God and broken the law. We are powerless to make amends on our own. We need God's help to change.
Yes, the law is important, but it is incapable of making us good. Only God can do that.