God's moral law cannot save us from sin and death.
Yet God's demand that we obey the Law stands.
These two facts would otherwise leave us eternally condemned and without hope. But as Saint Paul wrote to the first century church at Rome:
There is therefore now no condemnation for those who are in Christ Jesus. 2For the law of the Spirit of life in Christ Jesus has set you free from the law of sin and of death. 3For God has done what the law, weakened by the flesh, could not do: by sending his own Son in the likeness of sinful flesh, and to deal with sin, he condemned sin in the flesh, 4so that the just requirement of the law might be fulfilled in us, who walk not according to the flesh but according to the Spirit. (Romans 8:1-4)Jesus calls us to repent and believe in Him and the "good news" He brings. (Believing in Jesus isn't just affirming His Lordship. Even Satan can vouch for that. To believe in Jesus is to entrust our lives--past, present, and future--to Him and to Him alone.) Jesus says that all who believe in Him are saved from sin and death and live with God eternally.
So, what are the uses of God's Law today? Lutheran theology identifies three.
First: God's moral law acts as a hedge, protecting human beings, even those who refuse to acknowledge God's existence, from themselves and from one another. Human beings have an understanding of what is right and wrong. As C.S. Lewis points out in the opening chapter of Mere Christianity, the reason that human beings "quarrel," attempting to prove each other wrong and themselves right, is that, without even articulating it, they each believe in some baseline understanding of what is moral and what is immoral. Good governments and despotic ones alike, explain and justify their laws based on this moral law, encompassed in the Ten Commandments, whether they know the commandments or God or not.
Paul talks about this in Romans 2:14-16:
When Gentiles [non-Jews and particularly, Paul refers to Gentiles who have no awareness of God's moral law], who do not possess the law, do instinctively what the law requires, these, though not having the law, are a law to themselves. 15They show that what the law requires is written on their hearts, to which their own conscience also bears witness; and their conflicting thoughts will accuse or perhaps excuse them 16on the day when, according to my gospel, God, through Jesus Christ, will judge the secret thoughts of all.Without the law written on our hearts, the world would be in an even bigger mess than it is. Nothing would act as a hedge or curb against our inborn sin turning every piece of this planet into total anarchy. Luther said that were it not for the law curbing human impulses, believers in Christ would be like "lambs among ravenous wolves."
The second use of the moral law is to act as a mirror. God's moral law shows us how far we are from God's expectations for human beings. We see ourselves as we are and know that we are condemned to death by our sin.
Paul says, "All have sinned and fall short of the glory of God" (Romans 3:23).
Another New Testament writer, James, says, "Whoever keeps the whole law but fails in one point has become accountable for all of it" (James 2:10).
The proper "wages" for sin, Paul also writes, is death. And the absolute most the moral law can do for us is show us that we are sinners alienated from God and life.
Passages like that should give us pause, helping us to see ourselves truthfully and driving us to the God revealed in Jesus Christ for mercy and forgiveness.
Jesus' parable about the son who "came to himself," recognizing how he had sinned against God and against his father, and returned to his father, willing to be a slave and not a son, is a great picture of how the moral law acts as a mirror, turning us to the God we meet in Christ for forgiveness. By God's grace--His charitable, forgiving love for sinners, all who repent and believe in Jesus are saved from sin and death. The mirror of the Law shows us that, without this grace we're lost to God forever and sends us to Christ in desperation.
The third use of the moral law is to act as a guide for those who already are living in relationship with Jesus Christ. This is the use the psalmist had in mind when he wrote:
Search me, O God, and know my heart;This side of our own death and resurrection, believers who have been made into Christ's new creation must nonetheless live with our old sinful selves. Without attention to God's commandments and submission to Christ's authority over our lives, it becomes easy to slide into sinful patterns which, if left unchecked, could take us into unbelief or willful sin. The third use of God's moral law helps believers face the truth about themselves and to keep turning to Christ for forgiveness and new life.
test me and know my thoughts.
See if there is any wicked way in me,
and lead me to the way everlasting. (Psalm 139:23-24)