[Luther] applies himself to maintain his mission as extraordinary and divine. In a letter he wrote to the bishops, "falsely so styled," said he, he assumed the title of Ecclesiastes [Ecclesiastical Superior], or Preacher, of Wittenberg, which none had ever given him; nor does he pretend anything else, but that he granted it himself; that so many bulls, and so many excommunications, so many condemnations from the pope and emperor, had stripped him of all his former titles, and defaced the character of the beast in him; yet he could not remain without a title, and had therefore given himself this, as a token of the ministry to which God had called him, and which he had received not from man, nor by man, but by the gift of God, and by the revelation of Jesus Christ.
Here we have his vocation as immediate, and as extraordinary, as that of St. Paul. On this foundation, at the beginning, and throughout the entire body of the letter, he qualifies himself as "Martin Luther, by the grace of God Ecclesiastes of Wittenberg;" and declares to the bishops, lest they should pretend ignorance, that this is his own title which he bestows on himself, with an egregious contempt of them and Satan; and that he might, with as good a claim, have called himself Evangelist by the grace of God; for Jesus Christ most certainly named him so, and considered him as Ecclesiastes.
By virtue of this celestial mission he did every thing in the church: he preached, he visited, abrogated some ceremonies, left others remaining, instituted and deposed. He, that never was more than a priest, dared to make, I do not say other priests, which itself would be an attempt unheard of in the entire Church since the origin of Christianity; but, what is much more unheard-of, even a bishop. It was deemed expedient by the party to invade the bishopric of Nuremberg. Luther went to this city, and by a new consecration ordained Nicholas Amsdorf bishop of it, whom he had already made minister and pastor of Magdeburg. He did not, therefore, make him bishop, in the sense he sometimes calls by that name all pastors, but he made him bishop, with all the prerogatives annexed to this sacred name, and gave him that superior character which himself had not: but all was comprised in his extraordinary vocation; and an Evangelist, sent immediately from God like another Paul, could do all he pleased in the church.
Such attempts as these, I know very well, are considered nothing in the "new reformation". These vocations and missions, so much respected in all ages, are nothing more, after all, than formalities to these new doctors, who require only what they call essentials; but these formalities established by God, preserve what is essential. They are formalities, if they please, but in the same sense the sacraments are so — divine formalities, which are the seals of the promise, and the instruments of grace.
'Vocation, mission, succession, lawful ordination,' are alike with them to be called formalities. By these sacred formalities God seals the promise he made to his church of preserving her for ever. "Go, teach and baptize; and lo, I am with you always, even to the end of time" - with you, teaching and baptizing, not with you here present only, and whom I have immediately chosen, but with you in the persons of those who shall be for ever substituted in your place by my appointment. Whoever despises these formalities of legitimate and ordinary missions, may, with the same reason, despise the sacraments, and confound the whole order of the church.
And without entering further into this subject, Luther, who said he was sent with an extraordinary title immediately from God as an evangelist and apostle, was not ignorant himself that that extraordinary vocation ought to be confirmed by miracles. Therefore, when [Thomas] Müntzer, with his Anabaptists, assumed the title and function of a "pastor," Luther would not suffer the question to turn on what he might call essential, or admit he should prove his doctrine from the Scriptures; but ordered he should be asked, "Who had given him commission to teach. Should he answer — God ; let him prove it," says Luther, "by a manifest miracle; for when God intends to alter anything in the ordinary form of mission, it is by such signs that he declares himself."
Luther had been educated in good principles, and could not avoid sometimes returning to them. Witness the treatise which he wrote of the authority of magistrates, in 1534. This date is remarkable, forasmuch as four years after the Augsburg Confession, and fifteen after the rupture, it cannot be said that the Lutheran doctrine had not at that time taken its form; and yet Luther there declared again, "That he had much rather a Lutheran should leave the parish, than preach there against his pastor's consent; that the magistrate ought not to suffer either private assemblies, or any to preach without lawful vocation; if they had suppressed the Anabaptists when they began to spread their doctrine without vocation, the many evils which desolated Germany would have been prevented; that no man truly pious should undertake anything without vocation, which ought to be observed so religiously, that even an 'Evangelical' (for so he calls his own disciples) might not preach in the parish of a papist or a heretic, without the consent of him who was pastor of it" which, proceeds he, in warning to the magistrates, "that they might shun those prattlers, who brought not good and sure testimonials of their vocation, either from God or men; without this, though they preached the pure gospel, or were angels dropped from heaven, yet they ought not to be admitted." This is to say, sound doctrine is not sufficient; but, besides this, one of two things is requisite, either miracles to testify God's extraordinary vocation, or the authority of those pastors who were already qualified to confer the ordinary vocation in due form.
When Luther wrote this, he was well aware it might be asked, whence he himself had received his authority? ... [W]hen he spoke with this assurance of his church, the question was: who had given him a charge of it; and how that vocation, which he had received with dependence, all of a sudden became independent of the whole ecclesiastical hierarchy?
Histoire des variations des églises protestantes
(History of the variations of the Protestant churches)