The Gospel is preached for salvation: this is what properly belongs to it; but believers alone are partakers of that salvation. In the mean time, its being an occasion of condemnation to unbelievers—that arises from their own fault. Thus Christ came not into the world to condemn the world, (John iii. 17,) for what need was there of this, inasmuch as without him we are all condemned? Yet he sends his apostles to bind, as well as to loose, and to retain sins, as well as remit them. (Matt. xviii. 18; John xx. 23.) He is the light of the world, (John viii. 12,) but he blinds unbelievers. (John ix. 39.) He is a Rock, for a foundation, but he is also to many a stone of stumbling. (Isaiah viii. 14.) We must always, therefore, distinguish between the proper office of the Gospel, and the accidental one (so to speak) which must be imputed to the depravity of mankind, to which it is owing, that life to them is turned into death.John Calvin, “Commentary on the Epistles of Paul the Apostle to the Corinthians,” in Calvin’s Commentaries, trans. J. Pringle, 22 vol. (Grand Rapids: Baker, 1981), 20:161.
Along the same lines, in his comments on Romans 1:16, Calvin said:
The gospel is indeed offered to all for their salvation, but the power of it appears not everywhere: and that it is the savour of death to the ungodly, does not proceed from what it is, but from their own wickedness.These quotes by other Reformed theologians say the same:
James Nalton (c.1600–1662):
...the Gracious pardon of God that is tendered in the Gospel, does not kill, or condemn any in it self, or in its own Nature, but through the contempt of those that do disregard it, in this regard, not simply, but accidentally, through the Corruptions of men’s hearts, and Natures, in this regard, the Gospel may be said to increase a man's curse and condemnation...Matthias Martinius (1572–1630):
...and the gospel, which in itself is a savor of life unto life, becomes to the unbelieving a savor of death unto death, by accident, through their own fault,...William Fenner (1600–1640):
It was Christ’s primary purpose, and the first end of his coming, to save the world: it is an accidental end, or rather an event of his coming, that the world is condemned.Bio: