The Gospel confirms and fulfills the Law

If you consider yourself "Reformed," I'm glad to hear it. But what I have noticed is that many who throw the label of Calvinist around in conversations over coffee or in the small group or in Sunday school are doing so merely from their experience through a John Piper sermon, a Kevin DeYoung blog, an R.C. Sproul book, or a Michael Horton radio broadcast. These men and organizations are wonderful, and I am thankful for them, but much of the content of their theological views merely articulate the thoughts of someone else, simply tweaking it and packaging it up for the modern reader. Please don't get me wrong - by grace, I have grown through these men and their ministries. I am indebted to them and would not be as confessionally informed without the message of the Kingdom they conveyed through their thoughts and words. But let's face it, they would probably be the first to admit that many of the things they say are derivative and hinge off the ground-breaking work done by other men: namely, John Calvin himself. So if you are a Calvinist and want to rightly bear the name, I encourage you to read Calvin's magnum opus, Institutes of the Christian Religion. Here is something an old pastor once said to me - read the older books first, then move to some of the works written more recently, and in so doing, I imagine you'll hear the echoes of the great Reformer dripping from their pages.

Here Calvin tries to clarify the important (but oft misunderstood) relationship between the ideas of Law and Gospel: 

The contrast thus made is by no means to be rejected, because, by the term Law, Paul frequently understands that rule of holy living in which God exacts what is his due, giving no hope of life unless we obey in every respect; and, on the other hand, denouncing a curse for the slightest failure. This Paul does when showing that we are freely accepted of God, and accounted righteous by being pardoned, because that obedience of the Law to which the reward is promised is nowhere to be found. Hence he appropriately represents the righteousness of the Law and the Gospel as opposed to each other. But the Gospel has not succeeded the whole Law in such a sense as to introduce a different method of salvation. It rather confirms the Law, and proves that every thing which it promised is fulfilled. What was shadow, it has made substance. When Christ says that the Law and the Prophets were until John, he does not consign the fathers to the curse, which, as the slaves of the Law, they could not escape. He intimates that they were only imbued with the rudiments, and remained far beneath the height of the Gospel doctrine. Accordingly Paul, after calling the Gospel “the power of God unto salvation to every one that believeth,” shortly after adds, that it was “witnessed by the Law and the Prophets,” (Rom. 1:16; 3:21). And in the end of the same Epistle, though he describes “the preaching of Jesus Christ” as “the revelation of the mystery which was kept secret since the world began,” he modifies the expression by adding, that it is “now made manifest” “by the scriptures of the prophets,” (Rom. 16:25, 26). Hence we infer, that when the whole Law is spoken of, the Gospel differs from it only in respect of clearness of manifestation. Still, on account of the inestimable riches of grace set before us in Christ, there is good reason for saying, that by his advent the kingdom of heaven was erected on the earth (Mt. 12:28).(1, italic emphasis mine)

(1) Calvin, Institutes of the Christian Religion. Hendrickson Publishers, 2009, Bk II, Ch. 9, para. 4.