I have come to see Lutheranism as a house, whose external walls are
still feebly standing, but whose interior has been completed gutted.
The walls represent the doctrinal boundaries.  The interior was the
mystical union.

Why did the mystical union disappear?

Precisely by Luther making a category error in the matter of liturgy.
There are two layers when it comes to liturgy:  the text itself and
then the pious commentary and understanding of that text.

Because Luther did not distinguish these two, he moved the liturgy        into the category of adiaphora so that it could be "dealt with."  Thus     he is the unwitting father of creative worship - change the liturgy to      fit one's confession of the faith.

What one could wish Luther would have done was to address the matter catechetically and leave the liturgical text in place (much like we have done with the closing words of the Athanasian Creed - words that are certainly susceptible to horrific misunderstanding, but we did not change them.  Instead we taught their true meaning!)

Erich Heidenreich's insights on Liturgy List and LutherQuest are right on:  if the liturgy is fixed and stable (as in the Eastern tradition), it gives time to deal with errors that arise at the point of the pious
commentary on it (which may be incorrect) and which in time will be
exposed as being contrary to the very text and spirit of the liturgy
itself.  But where the liturgy is regarded as "adjustable" - well, it will be adjusted as faith changes instead of standing as a challenge to false
understandings.

Because Lutheranism was from the start set on a very shaky liturgical
foundation, it has inevitably slipped again and again into chaos.  It
has not had the wherewithal to withstand the onslaughts of challenges to the holy faith.  What is prayed is what is believed and what is believed is what is prayed.  What we should have realized right at the start of church growthery was that it was happening again - but above all we should have asked:  WHY does this continue to happen to us?  Why cannot the Lutheran Church sustain itself in the same way that other Churches have?

I am 99% convinced it is because for us the liturgical foundation is
inherently unstable and this results in the faith foundation also being
unstable.

This ties precisely to the gutting of the interior of the house because
it is the liturgy of the Eucharist that is the hearth from which the
warmth of koinonia with the Blessed Trinity fills the entire structure.
Remove that hearth and you have only the external structures of the
doctrinal walls left.  The reason things like 40 days of purpose keep
sweeping over our people and capturing them is because they are crying out to us that for all the fact that the walls are standing, the home inside has been destroyed.  When will we pastors have the eyes to see?
Some Thoughts on
Lutheranism and Stability

Pastor William Weedon