Law is incapable of changing people. Sure it could stop people from doing certain behaviors because they are afraid of the punishment, but those people wouldn't hesitant to do evil deeds if there were no consquences. So while outward appearance the appear to be good it is another story concerning their heart.
"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 tells us that what is just as important as our obedience to the Law is the condition of our heart. The Law cannot fix a heart twisted by sin, only the blood of Jesus Christ and the presence of the Holy Spirit can correct that problem. No amount of law keeping take away the consquences of sin in our lives.
What does that mean? It means that everyone is in the same boat, no matter how "good" the might appear. Without Jesus Christ in our lives there is nothing we can do to make up for the sin in our lives or restore our sinful heart to purity. What the Church has to offer to a world plagued with sin is not law, but grace. Change will only occur as people give their lives to Jesus Christ. We need to be people of grace rather than being people of law.