People sometimes ask: Since Christians are so insistent that God has forgiven ALL sins through the death of Jesus on the cross, why do we even worry about the Bible’s rules for behavior? If God pardons bad behavior without a blink, why even worry about it? Or to put it another way, doesn’t the Gospel (good news of salvation through Jesus) taught in the New Testament over-ride the laws taught in the Old Testament? Didn’t those become obsolete when Jesus died on the cross?
Now, we first have to make an important distinction between two kinds of “Law.” One kind is all of the ritual rules (like what you can eat and how to shave your beard) that God gave the Jewish people in the Old Testament to emphasize His special covenant with them. Those laws did become void for Christians living under the New Covenant (Do God’s Laws Ever Become Obsolete?). On the other hand, the moral laws (like the Ten Commandments) are for all time, and in fact Jesus amplified them in the Sermon on the Mount (Matthew 5:17-48). So when we talk about Law here, we mean the moral laws that reflect God’s will for acceptable human behavior. When we violate those laws, we sin. But since Jesus forgave our sins by His death, why should we still take those laws seriously? If the IRS stops prosecuting, why pay taxes? The tax laws would have become essentially pointless! Isn’t it the same with God’s laws in view of the forgiveness of sins?
Lutherans have traditionally answered this question by talking about three uses of God’s moral Law:
First Use: As a ‘curb’. The idea here is that rules are a necessity for an orderly and harmonious society; think of how the curb on a street prevents people from driving on other people’s lawns. Rules against stealing, adultery, killing, slander, etc. curb behaviors that harm innocent people and which create discord and mistrust. This is sometimes called the ‘civil use’ for the Law since it helps regulate society for everyone’s benefit.
Second Use: As a ‘mirror.’ The idea here is that the Law drives us to the Gospel by showing us how badly we need it. It’s like the complacent “couch potato” who goes to the gym after he catches a glimpse of himself naked in the full-length mirror! Similarly, when we start to feel self-righteous, a frank look at ourselves in the mirror of God’s righteous Law quickly dispels any notion that we’re doing fine on our own! We see that we’re doomed without Jesus! That’s why this is often called the theological use of the Law.
The third use of the Law is trickier: It’s often been compared to a ‘ruler’ or ‘yardstick’ but that has sometimes encouraged people to use the Law to measure (judge) other people’s behavior. Wrong! Rightly understood, this use of the Law is understood as the desire of every true disciple of Jesus to personally conform as closely as possible to His example of obedience. We want to do that, not because we have any illusions that our “good behavior” makes us any more righteous on our own, but simply because of our love and gratitude. The moral Law of God, which Jesus perfectly embodied, thus is the standard of behavior by which we try to emulate Him.
Understanding these three uses helps us recognize that God’s laws are not arbitrary creations to test us – like hurdles we have to jump over or burdens we have to bear – but rather His gracious gifts to guard our earthly well-being, to keep us focused on Jesus for our salvation, and to guide us in our lives of discipleship.
The law of the Lord is perfect, reviving the soul; the testimony of the Lord is sure, making wise the simple; the precepts of the Lord are right, rejoicing the heart; the commandment of the Lord is pure, enlightening the eyes; the fear of the Lord is clean, enduring forever; the rules of the Lord are true, and righteous altogether. More to be desired are they than gold, even much fine gold …” (Psalm 19:7-10a)