Midway through his essay, Sasse cites Augsburg Confession, Article VII, on the Church. Here is the translation of that article from Concordia: the Lutheran Confessions:
Our churches teach that the one holy Church is to remain forever. The Church is the congregation of saints in which the Gospel is purely taught and the Sacraments are correctly administered (AC VII.1; Concordia, p. 34)
After citing AC VII, Sasse asks this important question and makes his crucial point:
Is this concept of the church antiquated? And if it is not, why has it not made the trip to America? It has not because it poses with inexorable seriousness the question which for our religious thought is final and most important: the question of truth.
The American concept of the church basically avoids this question. It surrenders dogma and liturgy as something unessential--"trifling matters" as Goethe put it. For us, however, both of these belong to the essence of the church: the Word and the Sacrament, confession and liturgy. We understand the protest against an ossified orthodoxy and a dreary ritualism, and we agree with this protest. But we believe that the church possesses in the Verbum Dei ["Word of God"] the eternal truth, over against all the relativism of human knowledge. and we believe that in the evangelically understood Sacraments of Baptism and the Lord's Supper, that in the liturgical life of the church which is grounded on these things, the powers are present which are able to establish a new and real human fellowship, even in an age in which all human fellowships are unraveling (Hermann Sasse, "American Christianity and the Church," in The Lonely Way: Selected Essays and Letters, Volume I (1927-1939), p. 47).
We American Christians do well to listen to our fathers in the faith.