Also, for Martin Luther, the real church consisted of people who hear the Gospel and proclaim it, Croghan said. The institutional church arose to aid that mission, “but institutions are not the church.” And, when to ensure their continued existence, such institutions compromise Gospel truth, they can be readily shed, Croghan said.
“The ELCA is not the church, by Luther's definition,” Croghan said.
In an article about congregations in South Dakota leaving ELCA, I came across this quote about ecclesiology. The rest of the article is good too.