To understand the Divine Service one must understand the Lutheran Reformation. The intent was never to strip the church of everything that came before in her 1500 years of history. What the Lutheran reformers did was to subject the doctrine and practice of the Church to Scripture.
This is important to grasp. Doctrine and practice that contradicted Scripture were reformed according to the Word of God; and if that was not possible, then they were abandoned. "Therefore, since the Mass among us follows the example of the Church, taken from the Scripture and the Fathers, we are confident that it cannot be disapproved. This is especially so because we keep the public ceremonies, which are for the most part similar to those previously in use" (Augsburg Confessions. Article XXIV par. 40).
The Lutheran Church accepts tradition that is subject to the Word of God. Universal tradition and local tradition. Both have places in the life of the Church. The Divine Service is made up of Word, Sacrament, & tradition.