Law is incapable of changing people. Yes, there is a certain segment obey the law because they are afraid of the punishment. The problem is these same people wouldn't hesitant to do evil if the negative consequences did not exist. By outward appearances they appear to be good their hearts are another story.
"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 seems to be saying that more important than our obedience is the condition of our hearts. The Laws job is to show us the best way to live. It reveals to us God's standard. The Law, however, cannot fix a heart twisted by sin. Only the blood of Jesus Christ and the presence of the Holy Spirit, accepted by faith, can correct our sin problem. No amount of law keeping take away the consequences of sin in our lives.
What does that mean? It means that everyone is in the same boat, no matter how "good" they might appear. Without Jesus Christ in our lives there is nothing we can do to make up for the sin we have committed or restore our corrupted heart to purity. What the Church has to offer to a world plagued with sin and death is not law, but grace. This sick and dying world needs to hear the truth about God's grace. Change will only occur as people respond to God's grace and give their lives to Jesus Christ. We need to be people of grace rather than being people of law.