In Karl Adam’s book, Roots of the Reformation, trans. by Cecily Hastings (Coming Home Resources: 2000), pages 25-26, it says:Had Martin Luther then arisen with his marvelous gifts of mind and heart, his warm penetration of the essence of Christianity, his passionate defiance of all unholiness and ungodliness, the elemental fury of his religious experience, his surging, soul-shattering power of speech, and not least that heroism in the face of death with which he defied the powers of the world—had he brought all these magnificent qualities to the removal of the abuses of the time and the cleansing of God’s garden from weeds, had he remained a faithful member of his Church, humble and simple, sincere and pure, then indeed we should today be his grateful debtors. He would be forever our great Reformer, our true man of God, our teacher and leader, comparable to Thomas Aquinas and Francis of Assisi. He would have been the greatest saint of the German people, the refounder of the Church in Germany, a second Boniface…
But—and here lies the tragedy of the Reformation and of German Christianity—he let the warring spirits drive him to overthrow not merely the abuses in the Church, but the Church Herself, founded upon Peter, bearing through the centuries the successio apostolica; he let them drive him to commit what St. Augustine called the greatest sin with which a Christian can burden himself: he set up altar against altar and tore in pieces the one Body of Christ.