ABSTRACT: St. Paul warns the Galatians that even if he or an angel from heaven should preach a Gospel other than the one they had received, let him be anathema (Gal. 1:8). What is that Gospel? How is one to judge other gospels (which are really no gospels at all)? And what does this Gospel mean for Church? We’ll embark on an ecclesiological quest—seeking the source of the Church’s authority and how it is that our Lord desires to deal with us. To do so, we’ll wrestle a bit with Scripture and Tradition—trying to clarify what exactly Sola Scriptura is—as well as doctrine and practice—highlighting the Catholic Principle of the Lutheran Confessions. Without separating the two, nor confusing them, we’ll try to order each as the Lord has given them, drinking from the stream as it leads us to the source. Scripture, Irenaeus, and Luther will be our dialogue partners along the way, neither preaching another Gospel, nor adding wood, hay, or straw, but building upon the foundation with gold, silver, and precious stones, that when tested by fire, we may be saved.