The following quote is from Klemet Preus’ extremely helpful book on the relationships between Doctrine and Practice (which I highly recommend to anyone who struggles with why many of us see the contemporary worship movement as a danger to Christianity/confessional Lutheranism). This quote addresses the relationship between the Lutheran understanding of Law v. Gospel and uniformity in the Divine Service:
The second question we need to answer about worship is: “Who is God talking to?” God has two messages. He speaks Law and He speaks Gospel. The Law is God’s message of judgment against my sin. The Gospel is God’s word of forgiveness in Christ. It is His gracious response to my guilt.
The Law differentiates. It distinguishes. It says that I have failed God and I have failed you, my brothers and sisters. You might have something against me as well. The Law forces me to measure myself against the standard of the Ten Commandments. And the Law has the nasty ability of making me better or worse than you.
The Gospel makes us all the same. When I am serving my neighbor, then I am different and unique. We will see that in the chapter on good works. But when I am being served by the Gospel, then I am just like every other sinner. I am equally sinful as you. And I am equally forgiven as you. We are the same. We are identical. Of course, my sins might be more profound, more heinous, and more creative than yours. But in Christ both you and I are bespoken righteous, clothed and covered in the righteousness of the heavenly Bridegroom, and cleansed in the blood of the Lamb. Sin, which makes us different and which divides, is forgiven. Good works, which distinguish and divide us, are irrelevant when it comes to salvation. So we are the same. The Divine Service reflects this.
If we are all the same, the services we attend should be pretty much the same. And if all the Christians in the world are the same, if the church is really “catholic,” then the worship services throughout the world should be pretty close to the same. If the saints from age to age are the same, and they are, then the worship services from age to age reflect our oneness and sameness in Christ. To whom is God speaking in the Divine Service? He is speaking His eternal changless word of forgiveness to His saints who are united into one holy people through that blessed Word.
But if worship is primarily me serving God, then my worship will be different than yours because we are different in our good works. Worship will then be far from uniform. If we get the direction of the communication right in worship, then we will also understand that uniformity in worship is good.
I particularly like his point that good works, though commanded by God, are irrelevant when it comes to salvation/justification. I think it is helpful especially in light of recent discussions on contraception. What we are talking about is the Law, good works, things necessary for our life here on earth. In this way the Law differentiates. We are different. One thinks contraception is evil. Another thinks it is the greatest thing in the world. But before God, we are all sinners equally, and we are all justified equally. God’s salvation is for us all without measurement, without regard to our faithfulness or lack thereof to keeping God’s Law. This is something for which we should all be thankful.