Does the Christian need God’s Law for Christian living and what is the use and purpose of God’s Law for a person after they have become a Christian? In fancy theological terms, is there a need for what is called, “The Third Use of the Law?” It seems to me that there are two opposing errors in response to these questions by well meaning Christians.
The one error leans toward Legalism and says that we live by the power and motivation of the Law. Keep in mind that the Law initially reveals sin and damnation to these folks, the Gospel saves them and then they return to the Law as a source of hope and inspiration for victorious living. The 3rd part of this Law-Gospel-Law scheme (i.e. the Law after the Gospel) essentially can negate and diminish the centrality of the Gospel. Instead of deriving one’s identity, motivation and assurance from the Gospel, these individuals ever so slightly shift their main attention back towards the Law, demoting the Gospel to a mere assumption.
On the other hand, Antinomians err when the Law is removed from the life of the Christian completely. This leads to lawlessness and spiritual apathy. A deliberate, unashamed, lifestyle of sin essentially repudiates and denies all that the Cross of Christ stands for.
Both the Antinomian and the Legalist are in error. The Antinomian simply negates the Law and the Legalist trusts in the Law as if it were the Gospel.
Friedemann Hebart has a neat little book that is out of print called, “One In The Gospel.” In this book he talks about the Law in the life of a Christian saying,
“Does the Christian need God’s law at all? If we are Christians who ‘live by the Spirit’ won’t we automatically do what God wants? The trouble is that we are not only accepted saints; we are also self-centered sinners and we do not always automatically love God and others. And so, when it comes to recognizing what God’s will is in any situation, our vision is clouded: ‘If believers…were perfectly renewed in this life through the indwelling Spirit…they would do what they are obligated to do…spontaneously and unhindered…But in this life Christians are not renewed perfectly and completely. (Luther)’ Therefore they need God’s commands ‘to light their way.’ God’s commands are an expression of his will for us.”
In other words, due to our sinful nature our understanding of God’s will is clouded; our reason is often off center. The Law not only reveals sin (i.e. second use) but it also shows us what is good and true, what God’s will is (i.e. third use).
Praise be to God that His will is not some mysterious abstract idea that we need to search for by spiritual speculation and mysticism, but is printed plainly in the Word.
So, yes, there is a need for the Law in the life of a Christian. There is a twofold caution to be aware of though.
First, we always need to keep in mind that the Law only reveals to us God’s will but it does not give us any power to fulfill its conditions. In the words of Robert Kolb,
“The Law cannot turn sinners to faith and produce proper behavior performed simply for the sake of God.”
Secondly, when we ponder the Law we can so easily drift back into believing/doing good works from the motives of: fear of punishment or the desire for a reward. Thus we end up forgetting the Gospel and can become Saints of Cain. We error in performing the works of the Law for and from the context of self rather than for the sake of God. According to Michael Horton,
“We always gravitate back towards ourselves: ‘Prone to wander, Lord, I feel it; prone to leave the God I love.’ We wander back towards self-confidence just as easily as into more obvious sins… In every generation, our natural tendency is to put the focus back on ourselves—our inner life, piety, community and actions…”
Keep in mind that these errors are not due to the Law itself. These errors are due to our improper understanding of the Law and our sinful nature.
So, does the Christian need God’s Law for Christian living? The answer is, “Yes.” However, it is a yes knowing full well that we tend to misuse the good Law.
 Friedemann Hebert, One In The Gospel: The Formula of Concord for Our Day (Openbook Publishers, 2000), 76.
 Robert Kolb, The Christian Faith (Concordia Publishing, 1993), 110.
 Michael Horton, Christless Christianity (Baker Books, 2008), 120, 122.