...a single illness threatens the Lutheran Churches of the world. It is the very secularization of the church itself. If 25 years ago the secularization of culture was recognized as the great illness of the time, then it is soberly to be asserted today that secularism is now the illness of the church. It is gripping to see that, in order to fulfill the missiological goal of calling the peoples of the west back to the Christian faith, the church itself must first be turned back to this faith. "Sweden's people are God' people." That was the solution a generation ago. Today the question is to what extent the Church of Sweden is still the church of God? And so it is in all nations. Great missionary endeavors and evangelization efforts will still be carried out, but it is precisely the most serious evangelists who are coming to the conviction that the gospel preaching church must be the first object of their evangelization. This understanding was already once given as a gift to German evangelical churchdom. The consequence of the theology of Karl Barth in the time of his great influence in the first half of the 1930's was based upon this recognition. That was the meaning of his struggle against Dibelius and his "Century of the Church." That was the most profound power of the "Confessing Churches" of all persuasions in Germany, however they may have differed from each other as Lutherans, Reformed, or United [Churches]. That was really the renewal of the Reformation; for Reformation is indeed the repentance of the church.
From The De-Confessionalization of Lutheranism?
Letters to Lutheran Pastors No. 22, New Year 1952
Trans. by Rev. Matthew Harrison
Available on-line here: http://www.clai.org.au/articles/sasse/deconfes.htm
Note - Sasse wrote these words almost half a century ago. What would he say today when almost everywhere the Lutheran Church has lost its inner spiritual power and in some places has imported secular methodologies into its mission and evangelism 'programs'? The call to repentance is perhaps more relevant and urgent now than when Sasse urged it upon the church of the 1950s.