At the heart of the reformation's hermeneutics was the distinction between "Law" and "Gospel." ... The Law condemns and drives us to Christ, so that the Gospel can comfort without any threats or exhortations that might lead to doubt.
We often hear calls to "live the Gospel," and yet, nowhere in Scripture are we called to "live the Gospel." Instead, we are told to believe the Gospel and obey the Law, receiving God's favor from the one and God's guidance from the other. The Gospel--or Good News--is not that God will help us achieve his favor with his help, but that someone else lived the Law in our place and fulfilled all righteousness.
Others confuse the Law and Gospel by replacing the demands of the Law with the simple command to "surrender all" or "make Jesus Lord and Savior," as if this one little work secured eternal life.
Earlier this century, J. Gresham Machen declared, "According to modern liberalism, faith is essentially the same as 'making Christ master' of one's life...But that simply means that salvation is thought to be obtained by our obedience to the commands of Christ. Such teaching is just a sublimated form of legalism."(1)
In another work, Machen added, What good does it do to me to tell me that the type of religion presented in the Bible is a very fine type of religion and that the thing for me to do is just to start practicing that type of religion now?...I will tell you, my friend. It does me not one tiniest little bit of good...What I need first of all is not exhortation, but a gospel, not directions for saving myself but knowledge of how God has saved me. Have you any good news? That is the question that I ask of you. I know your exhortations will not help me. But if anything has been done to save me, will you not tell me the facts?(2)
Does that mean that the Word of God does not command our obedience or that such obedience is optional? Certainly not! But it does mean that obedience must not be confused with the Gospel. Our best obedience is corrupted, so how could that be good news? The Gospel is that Christ was crucified for our sins and was raised for our justification. The Gospel produces new life, new experiences, and a new obedience, but too often we confuse the fruit or effects with the Gospel itself. Nothing that happens within us is, properly speaking, "Gospel," but it is the Gospel's effect. Paul instructs us, "Only let your conduct be worthy of the gospel of Christ..." (Phil. 1:27).
But there are many, especially in our narcissistic age, whose ignorance of the Law leads them into a carnal security. Thus, people often conclude that they are "safe and secure from all alarm" because they walked an aisle, prayed a prayer, or signed a card, even though they have never had to give up their own fig leaves in order to be clothed with the righteousness of the Lamb of God.
Thus, Machen writes,A new and more powerful proclamation of law is perhaps the most pressing need of the hour; men would have little difficulty with the gospel if they had only learned the lesson of the law. As it is, they are turning aside from the Christian pathway; they are turning to the village of Morality, and to the house of Mr. Legality, who is reported to be very skillful in relieving men of their burdens... 'Making Christ Master' in the life, putting into practice 'the principles of Christ' by one's own efforts--these are merely new ways of earning salvation by one's obedience to God's commands. And they are undertaken because of a lax view of what those commands are. So it always is: a low view of law always brings legalism in religion; a high view of law makes a man a seeker after grace.(3)
--Michael S. Horton (with quotes from J. Gresham Machen)
(1) J. Gresham Machen, Christianity & Liberalism (Erdmans, 1923), p. 143.
(2) J. Gresham Machen, Christian Faith in the Modern World (Macmillan, 1936), p. 57.
(3) J. Gresham Machen, What is Faith? (Macmillan, 1925), pp. 137, 139, 152.