c. 1666-69. Oil on canvas. Nationalmuseum, Stockholm, Sweden)
The difference between the Reformed and Lutheran understanding of the law, specifically its third use, is significant. Although the Formula deals with the third use in a somewhat abbreviated way, Luther’s explanations to the Ten Commandments along with his catechism hymn, may be the simplest and most brilliant treatment of the law in its third use. While dealing with the first use of the law (usus civilis), and the second use (usus elenchticus), he proceeds to lay out a third use (tertius usus legis), which shapes and defines the new reality of the Christian life insofar as he is truly converted and Christian. Besides being a curb and mirror of sin, thus accusing and preparing for the Gospel, the law functions in a wholly new and different way for the life of the regenerate who is made righteous through Jesus. The law no longer comes by way of crushing imposition that destroys the sinner. The negative requirements and prohibitions are reversed and take on a positivistic role in the life of the believer, thereby becoming what Dr. David P. Scaer calls “Christological descriptions, first of Jesus and then of believers.” When the law is fulfilled by Christ and appropriated into the life of the Christian, it no longer confronts the sinner as in its accusatory sense (2nd use) and threat but as Christological statements that recall how they were received prior to man’s fall. Therefore the law of Moses (Torah) is apostolic Gospel in that it is descriptive of who God Himself is – realized in the incarnation, life, death, and resurrection of Jesus.
In the third use of the law, the Christian is and does that which corresponds to faith in Jesus. Maybe this is why Luther recommends that after morning prayer the Christian may sing “These are the Holy Ten Commands,” suggesting the Christian “…Then go joyfully to your work” (LSB Morning Prayer). The regenerate Christian does not move about by the coercion of the Law, but by the renewing of the Holy Spirit, voluntarily and spontaneously from the heart. The Lutheran understanding of the third use of the law proceeds from an anthropology that sees man as simul iustus et peccator. Even though the law becomes descriptive of Christ and therefore the life of the Christian, it is not to say he is no longer sinner but in fact remains one until death or Christ’s Second Coming.
While the Lutherans place a great deal of emphasis upon the accusatory nature of the law, the Reformed prefer to see in the law primarily directives for the Christian life. The reality of the simul iustus et peccator does not hold a significant place in their thinking. The Reformed are more interested in incremental sanctification rather than the centrality of justification through the merits of Jesus. The law holds an educational utility in that it actually leads to Christ. For the Reformed, Jesus is more like a help or instrument for another result, namely obedience and motivation. He never really gets anything done for the sinner beyond serving as exemplary model par excellence.
Lutherans have always opposed the idea that the Law by itself leads a sinner to Christ. Unlike the Reformed, Lutherans hold that believers fulfill the law not as command but as it has been fulfilled and completed in Jesus. Christians therefore are not moved by the law’s threats but are moved to do good works by the Gospel alone. New obedience (AC VI) is an article of faith, in which Lutherans confess that Christ in the believer brings forth good fruit by the work of the Spirit. This reality is rooted squarely upon the article of justification which produces those works ex-nihilo.
The idea of spontaneous works of the spirit and new obedience springing forth purely from faith in the Gospel alone, does not really fit into the Reformed understanding of the third use. The Gospel alone does not move the regenerate along in his daily sanctification, but the law remains as a force to prod the believer into good works. For Calvin and the Reformed, God’s glory is made manifest in proper moral behavior through discipline and adherence to the law. The law accompanied by faith produces good works. This is a false view of the third use and indicates a weak or more accurately an absent Christology and therefore leaves no room for justification. For Lutherans, faith hears the Gospel and partakes of Jesus righteousness and lives that righteousness (third use), because it has been fulfilled and won through Christ’s blood. The erroneous suspicion from Rome and the Reformed is that Lutherans are antinomian in orientation. It is helpful to remember that Jesus was charged with the same.