For your consideration…
The first care, then, of all who work in the field of English Mission, pastors and laymen alike, ought ever to be that they steadfastly adhere to the biblical doctrine in all its parts. Lutheran hymns, Lutheran liturgies, Lutheran prayers, above all Lutheran sermons ought to be heard wherever our missionary work is carried on. True Lutheranism need not fear any criticism. It has stood the test of centuries, and no modern weapon of offense will subvert it. It is an impregnable fortress. Be not afraid, then, to show its beauties to all who come to hear. They expect to be treated to something new in our churches, and they ought not be disappointed. To follow the example set by sectarian clergymen, to sermonize on anything else rather than upon questions of doctrine, or to fill the hearers' ears with weak generalizations and pasture them on fine, poetic language alone, would be worse than folly. To make a good impression, to effect some real, living good, solid meat must be offered, which alone can satisfy the soul's desires. Emphasize doctrine, if you would accomplish your aim. Else why should we expend money and labor, only to do what others may do as well? (John Schaller, "Danger Ahead!", Lutheran Witness, Vol. 10, No. 8 [Sept. 21, 1891], pp. 57-58)
There are several things worth noticing in this brief quote. First, note that, for a Lutheran pastor, "steadfast adherence to biblical doctrine in all its parts" is equivalent to using "Lutheran hymns, Lutheran liturgies, Lutheran prayers, and Lutheran sermons." This is rather quaint, isn't it? How odd it must be for some Lutherans to hear someone speak in such a way about distinctively Lutheran practice, as if it is uniquely representative of biblical doctrine... But not for the Lutheran confessor, who is convinced as a matter of Christian conscience that his body of doctrine, apart from all others, carries the pure and unalloyed truth of God's Word.
There is no teaching of Lutheran Doctrine – that is, of true Christian doctrine – that can be taught apart from also teaching Justification. And only the message of Law and Gospel teaches Justification. Thus, Law and Gospel, properly divided and properly used and applied, is not only central to all Lutheran preaching and teaching, it is necessary to all Lutheran preaching and teaching.
By emphasizing doctrine, the Lutheran preacher cannot avoid what is central to all of our doctrines – the saving message of the Doctrine of Justification. Moreover, in order to preach and teach Justification, he must preach Law and Gospel. Period.