"It was night indeed in a great part of Christendom. Such is the conclusion of our survey of the end of the fifteenth century: amongst the common people, a fearful decline of true piety into religious materialism and morbid hysteria; amongst the clergy, both lower and higher, widespread worldliness and neglect of duty; and amonst the very Shepherds of the Church, demonic ambition and sacrilegious perversion of holy things. Both clergy and people must cry mea culpa, mea maxima culpa! [I am culpable, I am most culpable.]
Yes, it was night. 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 this 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 of the Church, but the Church Herself, founded upon Peter, bearing through the centuries the succesio 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."
-Karl Adam, from his book Roots of the Reformation.
*"There is nothing more serious than the sacrilege of schism because there is no just cause for severing [the] unity [of the Church]" -St. Augustine