Of like significance is Luther's advocacy of the separation of the temporal and spiritual powers, practically of Church and State,--the position which he develops later in the _Open Letter to the Nobility_. But in this treatise, again, Luther shows himself to be anything but the immoral monster his vilifiers have tried to make of him. He is again the man of conscience--will his critics say, "of oversensitive conscience"? Thank God that there were some sensitive consciences in an almost conscienceless age! Luther fears sin more than the ban, and sin has for him more than an ecclesiastical meaning. Sin is not primarily an act against the Church, but an offence against God. This the ban is to teach; it is to be the symbol of God's wrath against sin and it is to be used by the Church only remedially and in love. When so used it becomes the chastening rod of the dear Mother Church, provided it be accepted and borne in this spirit.
Why, then, did not Luther bear his own ban in this way? The justification for his subsequent conduct is to be found in two brief but important conditional clauses in this treatise. "God," he says, "cannot and will not permit authority to be wantonly and impudently resisted, _when it does not force us to do what is against God or His commandments_."[2] Again he says, "When unjustly put under the ban we should be very careful not to do, omit, say or withhold that on account of which we are under the ban, _unless we cannot do so without sin and without injury to our neighbor_."[3] God and his neighbor were for Luther the actors which made it necessary for him to speak and act, when for selfish reasons he would often rather have remained passive.
The inception of our treatise is to be found in a sermon preached in Wittenberg in the spring of 1518. Luther's pastoral concern for his people made it necessary for him to speak on this subject in order to quiet the consciences both embittered and distressed by the wanton and unjust use of the power of excommunication. Added to this must have been his own personal interest in the ban certain to fall on him. In a letter to Link[4], dated July 10, 1518, he speaks of having preached a sermon on the power of the ban which produced general consternation and fear that the ire enkindled by the XCV Theses would start afresh. He had desired a public disputation on the subject, but the Bishop of Brandenburg persuaded him to defer the matter. Under date of September 1st, Luther writes Staupitz[5] that because his sermon had been misrepresented and spread by unfriendly spies it became necessary for him to publish it. It appeared in August after Luther's summons to Rome, under the title _De Virtute Excommunicationis_. Our treatise is an elaboration in popular form of this Latin treatise of 1515.