John Calvin - The differences and similarities between the Law and the Gospel

...We see the error of those who, in comparing the Law with the Gospel, represent it merely as a comparison between the merit of works, and the gratuitous imputation of righteousness. 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, (Matth. 12: 28.)


- John Calvin (Institutes of the Christian Religion, 2.9.4)