Therefore the law is holy, and the commandment holy and just and good.
Romans 7:12
What is the Law Good for? Historically, the Law has been recognized as having three distinct uses.
The Law convicts people of sin so they will look to Christ for forgiveness (Galatians 3:24). Jesus did not come to cheer us up and encourage us to have happier lives. He came to save His people from their sins (Matthew 1:21). So what should we make of those who “accept Jesus into their hearts” with no thought of forgiveness of sin? The only thing we can think is that they are not saved.
No one thinks they need a Savior unless they know they are sinners in need of forgiveness. How does anyone know this? The Law. This does not mean that one must hear a sermon on the Law, or read the Law directly out of the Bible to be presented with one’s sinfulness. What it does mean is that to be saved, a person needs to know that he or she is a sinner in need of forgiveness. The Law is the primary source of knowledge regarding sin. The Law has never saved, nor made a person righteous. The Law only tells us how unrighteous we are so we that will respond to the good news of Christ and the gospel by trusting in Christ and turning from sin. Without the Law doing its part directly or indirectly, no one would ever be saved.
The Law restrains evil (Deuteronomy 17:7, 19:19, et al). This is true both for non-believers and believers.
Even non-believers desire to avoid the consequences of sin. Well-intentioned people work hard these days to convince us that punishment is not a deterrent to crime. God says it is, and He is right. The only time punishment is not a deterrent is if the punishment is not severe enough.
Believers are deterred from sin, not merely because of consequences, but because we do not want to sin against the Lord who loves us and gave His life for us!
The Law reveals holiness (Leviticus 19:2). The Law is filled with examples that teach what holy living looks like, teaching us how to live lives of grateful obedience—not in order to be saved, but because we have been saved by faith alone in Christ alone.
Whenever the Law is presented as the way to live to be saved—it is being used falsely and unbiblically.