Luther has indicated with sufficient distinctness that he merely conceded to his theological opponents theological terminology, and made use of it himself merely on account of traditional familiarity with it, and because the employment of incorrect words was not necessarily of evil. He so expressed himself with regard to the most important terms.
First of all he had an objection to all the different descriptions of justification: to justify, to be regenerated, to sanctify, to quicken, righteousness, to impute (justificare, regenerari, sanctificare, vivificare, justitia, imputare), etc., etc.; he felt very much that the mere number of the terms was a serious burden upon his conception, and that no single word completely answered to his view.
Secondly, in a similar way he objected to the word satisfaction (satisfactio) in every sense; as used by his opponents he will only let it pass.
Thirdly, he stumbled at the term “Church” (ecclesia); for it obscured or confused what should simply be called Christian community, gathering, or—still better—a holy Christendom.
Fourthly, he observed very clearly the objectionableness of the word “Sacrament”; what he would have liked most would have been to see that the use of it was entirely avoided, and that for the ambiguous formula “Word and Sacrament,” there was substituted the Word alone, or that if the term Sacrament was retained there should be a speaking of one Sacrament and several signs.
Fifthly, he himself declared such a term as ὁμοούσιος to be unallowable in the strict sense, because it represents a bad state of things when such words are invented in the Christian system of faith: “we must indulge the Fathers in the use of it … but if my soul hates the word homousios and I prefer not to use it, I shall not be a heretic; for who will compel me to use it, provided that I hold the thing which was defined in the Council by means of the Scriptures? although the Arians had wrong views with regard to the faith, they were nevertheless very right in this … that they required that no profane and novel word should be allowed to be introduced into the rules of faith.” In like manner he objected to and rather avoided the terms “Dreifaltigkeit,” “Dreiheit,” “unitas,” “trinitas” (threefoldness, threeness, oneness, trinity).
Yet, as is proved by the words quoted above, there is this difference observable here—that he regarded the terminologies of the mediæval theology as misleading and false, the terminologies on the other hand of the theology of the ancient Church as merely useless and cold.
But from still another side he objected most earnestly to all the results of theological labour that had been handed down from the days of the Apologists; and here in still greater degree than in his censure of particular conceptions his divergence from the old dogma found expression, namely, in that distinguishing between “for himself (itself)” and “for us,” which is so frequently to be found in Luther. Over and over again, and on all occasions, the definitions given by the old dogmatic of God and Christ, of the will and attributes of God, of the natures in Christ, of the history of Christ, etc., are set aside with the remark: “that He is for himself,” in order that his new view, which is for him the chief matter, nay, which constitutes the whole, may then be introduced under the formula “that He is for us,” or simply “for us.”
“Christ is not called Christ because He has two natures. What concern have I in that? But he bears this glorious and comforting title from the office and work which He has taken upon Him … that He is by nature man and God, that He has for Himself.” In this “for himself” and “for us” the new theology of Luther, and at the same time his conservative tendency find clearest expression.
Theology is not the analysis and description of God and of the divine acts from the standpoint of reason as occupying an independent position over against God, but it is the confession on the part of faith of its own experience, that is, of revelation.
This, however, puts an end to the old theology with its metaphysic and its rash ingenuity. But if Luther now nevertheless allows those old doctrines to remain under the terms “God in Himself,” “the hidden God,” “the hidden will of God,” they no longer remain as what are properly speaking doctrines of faith. About this no doubt can arise. But that they were not entirely rejected by him has its cause on the one hand in his believing they were found in Scripture, and on the other hand in his failure to think out the problems in a comprehensive and systematic way.*
Von Harnack- as always- observant and expressive and precise. The bold part is my emphasis. It is here that von Harnack has understood Luther’s theology in a way that NT Wright and other modern interpreters have not. And cannot, because they don’t understand Luther.
*History of Dogma. (N. Buchanan, Trans., T. K. Cheyne, Ed.) (Vol. 7, pp. 224–227).