“Without the gospel everything is useless and vain; without the gospel we are not Christians; without the gospel all riches is poverty, all wisdom folly before God; strength is weakness, and all the justice of man is under the condemnation of God. But by the knowledge of the gospel we are made children of God, brothers of Jesus Christ, fellow townsmen with the saints, citizens of the Kingdom of Heaven, heirs of God with Jesus Christ, by whom the poor are made rich, the weak strong, the fools wise, the sinner justified, the desolate comforted, the doubting sure, and slaves free.
The gospel is the Word of life and truth. It is the power of God for the salvation of all those who believe; and the key to the knowledge of God, which opens the door of the Kingdom of Heaven to the faithful by releasing them from sins, and closes it to the unbelievers, binding them in their sins. Blessed are all they who hear the gospel and keep it; for in this way they show that they are children of God. Woe to those who will not heart it and follow it; because they are children of the devil.”
–John Calvin, “Preface to Olivetan’s New Testament,” in Calvin: Commentaries (Library of Christian Classics, Vol. XXIII), Ed. Joseph Haroutunian (Louisville, KY: Westminster John Knox, 1958), 66-67. Available online here.