The law and the gospel each have their own tasks. Those tasks are not exclusive of each other. Just as Christians also have callings of various kinds: father, church member, child, employee, citizen, etc. and sometimes those callings have contrary expectations, so too the law and the gospel do not exclude each other in the Christian life, but each has its own purpose and function in our lives. Sometimes those functions of the law and gospel are very much contrary to each other. Martin Luther says that the law and the gospel are "non plus contraria," that is, the greatest opposites. According to the law we owe the sacrifice of our life, including a life of obedience to the divine will. That will never change. The trouble is that, even after we are firmly fixed in our Christian faith, we will still stumble over the law's implacable and unchangeable requirements. Our sacrifices are ever and always tainted by our perverse self-regard. The good that we know we should do, we don't do (Rm 7:15-21). This is the continual and agonized experience of the Christian. He knows and regards himself to be a sinner. This is why he needs Christ. If we could get clear of our wickedness on our own, Christ would have died for no reason (Gal 2:21).

Both the law and the gospel are great blessings to the church and her children. Both come from God and are for our good. Both are the word of God. But each has its own purposes and functions. We are to be obedient to the law for the sake of our neighbor. The law gives us a clear view of what is owed to our neighbor for God's sake. However, the law will always fulfill a critical role over against human self-righteousness. Every person remains under the law in its critical role as the pedagogue (Gal 3:25) that beats us into the admission that we need and will always need Christ. So this text: "But now that faith has come, we are no longer under a guardian" (Gal 3:25), must not be taken to mean that the law's pedagogical function ceases insofar as we need the law, but that it has no place where and when the gospel and its faith in Christ as mediator are established. As sinners, we still have need of the law's pedagogical and instructive functions. We seek to obey the law, but also recognize that because of the indwelling of the old Adam, we will always fall short. The gospel as the testimony to God's grace will always follow upon the law's work.

It is so easy, though, to get focused on the law and its work in our lives and to fall into a legalistic way of life or, worse yet, to despair of our salvation. This is why Luther suggested that the cry for mercy not only frees us from the accusations of the law and its accruing guilt, but that it must also drive our view of the divine blessings as well. The gospel must shape our whole life in Christ. This is a Christological necessity. If Christ is to be our God, He must also be our whole and entire salvation. That is Christ's work for us. To deprive Him of His saving activity is to deny His essential deity. Trust in Christ alone for salvation is a first commandment thing. If Christ is our God we will offer our obedience to the law, but for salvation always stand in the gospel alone.

Martin Luther