Our Lutheran Confessions identify the proper distinction of Law and Gospel as “an especially brilliant light” whereby the Word of God is rightly divided, explained, and understood (Formula of Concord, Solid Declaration, V.1). This distinction and dividing of Law and Gospel is one of the hallmarks of the Reformation, and it remains one of the most significant components of all our theological efforts. Certainly, it can be misconstrued and overdone in contrived and formulaic ways, but the distinctive place and purpose of both the Law and the Gospel must be maintained.
Although they are necessarily distinguished and “rightly divided,” it is both-and, not either-or; for both the Law and the Gospel are the Word of the Lord, both are good and right and true, and both are involved in God’s work of repentance within the hearts, minds, and lives of those whom He calls to Himself. Both the Law and the Gospel are to be preached, taught, and confessed, unto faith and love, according to the purposes for which the Lord has spoken and revealed His Word. And most important, both the Law and the Gospel find their heart and center, their meaning and fulfillment in Christ Jesus, in whom “righteousness and peace kiss each other” (Psalm 85:10).
Preaching and teaching the Law without the Gospel is legalism, whereas preaching and teaching the Gospel without the Law is licentiousness, and neither of these approaches is in keeping with the faith once delivered to the saints. Trying to use the Gospel to do the work of the Law is just as much a confusion of the two as trying to use the Law to do the work of the Gospel is.
The Law, as written on men’s hearts and in the conscience, curbs gross outbreaks of sin through threats of punishment and the promise of rewards – and this, in itself, is a kind of rough training ground, whereby the Lord teaches people right and wrong (and that there is indeed a difference!).
The revealed Law of God, as summarized especially in the Ten Commandments, always accuses us, because it exposes our sins and condemns them as contrary to the Word and Will of the Lord. It is our “mortal enemy,” not as though it were bad, but precisely because it is holy, righteous, and good, whereas we are conceived and born in sin and consequently sinful in our thoughts, words, and actions. This is and remains the primary work of the Law in this life on earth.
The “third use of the Law” (Formula of Concord VI) is not in our hands, to be determined by us. Rather, this is the way that God the Holy Spirit uses the Law to guide and govern the Christian in holy faith and holy love – which is to live as a disciple of the Lord Jesus Christ.
To be clear, the Law does not and cannot sanctify or save anyone; only the Gospel does that, by the forgiveness and justification of the Cross and Resurrection of Christ Jesus, now preached and administered by those who are called, ordained, and sent in His Name and stead. What is more, it is only by faith in that Gospel – in the righteousness and holiness of such faith – that a Christian is a Christian, has life with God in Christ Jesus, and so lives in harmony with the Law of God.
Such faith and life and love are obtained in us by God, in accordance with His good and gracious Will, as the Holy Spirit lays Christ upon our hearts through the Gospel, the forgiveness of sins. It is that Ministry of the Gospel which rescues from sin and death and bestows life and salvation.
Now, for the Christian, the Law does not simply provide facts, information, and knowledge, but actually determines, establishes, and reveals what is the good and acceptable and perfect Will of God (Romans 12:2). That is, His Word actually sanctifies that which is good and right and true, to make it so, and His people rejoice to live in harmony with His Word, by faith in His Word. As Luther describes so eloquently in the Large Catechism, in discussing the Fourth Commandment, the little kitchen maid delights in knowing that scrubbing the floor is pleasing to God because it is in keeping with His Word, and children honor the “hidden majesty” of God in their fathers and mothers because they are adorned and honored by His Commandment. Such good works, done in faith and love, are far and away superior to all self-invented works that lack the Word of God.
This is also the wisdom of God at work in Dr. Luther’s guidance and instruction concerning the Fifth Chief Part in the Small Catechism, where he advises the head of the household to teach his family and servants how to examine themselves for the sake of making confession and receiving Holy Absolution. “Consider your place in life according to the Ten Commandments,” he writes. That is how each Christian knows what is pleasing to the Lord within his or her proper calling and station in life. And that is also what then prompts the Christian to confess his or her sins and seek the saving grace of God in the only place it is ever to be found, in the Word of the Gospel. The Law thus works to serve the Gospel, repentance, faith, and love, while the Gospel does its own unique and proper work in forgiving sins and bestowing the Life of God in Christ Jesus.