In the mid-16th Century, Lutheran churches were pressured by force to reincorporate certain Papistic worship practices into their services. Those pastors who refused were deposed in many places. Others accepted the changes, saying those changes were really indifferent to the doctrine we teach and believe. The problem, as the Formula of Concord describes, was that these changes were commanded as an exercise in obedience to the special, divine authority of the Pope, and an admission that the papal doctrine is true. The Lutherans who objected were right to do so.
Today, Lutheranism is again split between those who want to change worship practices and those who do not. These days, the changes are innovations determined not by papal authority, but by the trends of worldly culture. They are not intended to be a form of submission, but a means of bringing the lost into contact with their Savior at church. The changes today might be characterized as a shift in focus from sacramental events (God coming to us, bringing His spiritual gifts) to sacrificial (We bringing our spiritual offerings to God), while also utilizing the entertainment emphasis in our culture to attract those who are drawn to such things.
The typical example of this shift is the incorporation of so-called “contemporary Christian music” into the liturgy. This category of music can be hard to define. Some try to define it by the instrumentation, but I think that’s really only one aspect of its character, and not essential. I would distinguish it by its entertainment-focused style, mimicking the various popular styles of music that play on the radio or that are downloaded from iTunes. This entertainment-focused style involves melody and harmonies, but especially rhythm and lyrics. It makes the musical experience into a performance for human consumption and appreciation. Spiritually, the music becomes a completely sacrificial event (see above) on the part of the performer, and very little — if any — sacramental value remains for the congregation. Instead, the congregants are asked to observe and enjoy the music as entertainment, the way they might enjoy a concert. Easily-felt emotional manipulation replaces sacramental significance, which can only be discerned by faith in God’s Word. Contrast this with traditional Lutheran hymnody and liturgy, in which everyone is a full participant (rather than being entertained), and where sacramental and sacrificial aspects exist in more or less equal proportions.
Thankfully, the same article in the Formula of Concord has something we can apply to these changes to our worship practices.
Likewise, when there are useless, foolish displays that are not profitable for good order, Christian discipline, or evangelical practice in the Church, these also are not genuine adiaphora, or matters of indifference. (Concordia: The Lutheran Confessions, FC, SD X, 7.)
If you would like to defend the present-day innovations generally called “contemporary Christian worship,” then I invite you to show how they are profitable for good order, Christian discipline, or evangelical practice in the Church.