http://weedon.blogspot.com/2010/05/thoughts-on-corrective-function-of.html:

My dear friend, Pr. Larry Peters, has written a fine piece you should read here. It raises a most interesting question in my mind about the extent to which a congregation or a Synod may honestly be considered "Lutheran." I would argue that when the documents comprising the Lutheran Symbols, the Christian Book of Concord, are no longer permitted to critique and challenge current teaching or practice; when instead our Church's Confession is relegated to the museum as an interesting artifact of what was once the case, then we have lost the right to the name "Lutheran." Whenever the Symbols are dismissed with "well, they can't mean THAT because we DO that and we're Lutherans after all," their corrective voice has been silenced and stilled. Well, not really. Rather ignored and shouted down. The voice of our fathers still rings out and it still challenges what we believe, teach, confess and practice. So are you and your congregation and your Synod ready to hear the living critique which the Symbols would offer? Then there might be hope for the Churches of the Augsburg Confession yet. If not, then shut out the lights, folks, and move on. Or, at least be honest and change the name on the door...

(HT: Issues, Etc., Blog of the Week)