It was not just at Wartburg Theological Seminary where the 3rd Use = Uses 1 & 2. Timothy Wengert was a co-editor of the 2000 English Edition of The Book of Concord. He was a professor of church history at The Lutheran Theological Seminary at Philadelphia. He did his seminary training at Luther in St. Paul. His Ph.D. came from Duke University. Among many other books, he wrote: A Formula for Parish Practice: Using the Formula of Concord in Congregations. I quote from his chapter on Article VI: Concerning the Third Use of the Law: "As we shall see, for the concordists the third use of the law was nothing but the first and second uses applied to Christians" (p. 91).
"The third use of the law reminds us of two things. First, Christians do not graduate from God's law to a higher form of existence. As long as we are in the flesh (which is going to be for a very long time), we are under the law. It curbs our inveterate addiction to ourselves, drives us to serve our neighbor whether we want to or not, and continues to show our desperate need for a Savior." (p. 94)
"The first use maintains order in this world and restrains our evil inclinations. The second use confronts us with our sins and, to use Luther's picturesque language, drives us to Christ. The third use of the law is a guide for the Christian life. Faced with certain Roman Catholic claims that the church could also prescribe things necessary for salvation, the reformers always insisted that only God's law, not humanly invented rules, revealed God's true desires. Although, as we shall see, this third use functions in ways not unlike the first and second uses, it does provide Christians with an outline of what God desires." (pp. 96-97)
"Thus, the third use of the law is nothing other than the first use (to order our lives toward what God wants and drive the old creature to do good) and the second use (to reveal our sin daily and thus to drive us to return to Christ and his forgiveness) applied to Christians." (p. 98)
"This article also implies that Christian as believers need not fear the law and its accusation but can finally discover there an invitation to life with God and the neighbor - the very thing the law describes but cannot give. Only when we confuse law and gospel (as many folks do who think they are defending the third use of the law) do things get turned upside down and (or course) the gospel disappears." (p. 100)