First, a Lutheran Sermon is exactly that, a Sermon that is distinctly Lutheran. It is a sermon that preaches Christ and Him crucified for the sins of the whole world (1 Corinthians 2:2). It is a sermon that preaches of the power of the Word of God (see document: What About…The Bible found here https://www.lcms.org/belief-and-practice). It is a sermon that preaches of the Sacraments. It is a sermon that preaches Sola Fide, Sola Gratia, Sola Scriptura, and Solus Christus (https://www.lcms.org/belief-and-practice)
Second, a Lutheran Sermon is grounded and adheres to the Lutheran Confessions, aka the Book of Concord. It adheres to its teachings because the Book of Concord is the right interpretation of Holy Scripture. (https://www.lcms.org/belief-and-practice)
Third, a Lutheran Sermon is an exegetical teaching of the Scriptures. The Pastor breaks down the Scriptures, interprets the original languages, pulls out meanings and important teachings within, and always points to Christ from the text.
Fourth, a Lutheran Sermon is preaching that displays both Law and Gospel. (Solid Declaration. Formula of Concord V)
These things should be self evident and should be enforced within the LCMS. However these principles in many cases are being ignored. And that is why this site and the podcast were created.
Also note, while https://www.lcms.org/belief-and-practice was cited multiple times, the Scriptures themselves can be consulted, and likewise the Book of Concord. The intent of this article is simply to provide a brief overview. A future article will present what is discussed here more in depth.