In the Missouri Synod's latest Rite of Ordination (published with LSB), pastors specifically promise to practice according to the Lutheran Confessions.
When you look through the Lutheran Confessions, you find various worship practices set forth. As you consider these practices, they fit within at least one of three categories:
Prescriptive – The Confessions say: "Do thus."
Proscriptive – The Confessions say: "Thus, thou shalt not do."
Descriptive – The Confessions say: "In times past, they did thus and so."
As you consider all of this, you might make a very natural assumption. A pastor should practice what the Confessions prescribe, and he should avoid what the Confessions proscribe, right?
I think so. And yet, I have been told many times (by pastors) that a pastor's worship practice is only bound to the "doctrinal articles" of the Lutheran Confessions.
In other words, there is a widely held view about the worship practices described in the Confessions. This view is that the worship practices set forth in the Confessions are not "doctrinal". They are merely descriptions of what happened in times and places that have little (if anything) to do with us today.
To be fair, the Confessions do contain such descriptive passages. Consider the following example:
Very few of our people today (at least in the States) would be instructed by hymns that are sung in the German language. This particular practice is one that fit people who belonged to a very specific location. When you look elsewhere in the Confessions, it does not seem that the confessors intended for the use of German (or Latin) to be binding upon anyone who wanted to adhere to their Confession. Consider this quotation from the Apology (XXIV:4-5):
So, yes, some of the worship practices that are included in the Confessions are merely descriptive. They may have been included simply to illustrate a point. No one should consider himself particularly bound to carry out such practices (like singing hymns in German) today.
That being said, it is also fair to say that there are passages within the Confessions that describe worship practices that should be considered binding. When we adopt the Lutheran Confessions as our own confession, we do not change the words. We do not say: "Their churches back in the sixteenth century retained the Mass, celebrated it with the highest reverence, and preserved nearly all of the usual ceremonies." When we make these Confessions our own confession, we say: "Our churches…".
Here, if you find discrepancies between what you do and what the Confessions say that you do, it might be a good moment for some honest reflection. If you find that the Confessions describe somebody else, that they don't really describe what you are doing – then maybe you should evaluate whether or not you really want these Confessions to be your confession after all.