Calvin's Institutes, Book 3, Chapter 24, 3.
3. Two errors are here to be avoided. Some make man a fellow-worker with God in such a sense, that man’s suffrage ratifies election, so that, according to them, the will of man is superior to the counsel of God.
As if Scripture taught that only the power of being able to believe is given us, and not rather faith itself. Others, although they do not so much impair the grace of the Holy Spirit, yet, induced by what means I know not, make election dependent on faith, as if it were doubtful and ineffectual till confirmed by faith. There can be no doubt, indeed, that in regard to us it is so confirmed. Moreover, we have already seen, that the secret counsel of God, which lay concealed, is thus brought to light, by this nothing more being understood than that that which was unknown is proved, and as it were sealed.

But it is false to say that election is then only effectual after we have embraced the gospel, and that it thence derives its vigor. It is true that we must there look for its certainty, because, if we attempt to penetrate to the secret ordination of God, we shall be engulfed in that profound abyss. But when the Lord has manifested it to us, we must ascend higher in order that the effect may not bury the cause. For what can be more absurd and unbecoming, than while Scripture teaches that we are illuminated as God has chosen us, our eyes should be so dazzled with the brightness of this light, as to refuse to attend to election?

Meanwhile, I deny not that, in order to be assured of our salvation, we must begin with the word, and that our confidence ought to go no farther than the word when we invoke God the Father. For some to obtain more certainty of the counsel of God (which is nigh us in our mouth, and in our heart, Deut. 30:14), absurdly desire to fly above the clouds. We must, therefore, curb that temerity by the soberness of faith, and be satisfied to have God as the witness of his hidden grace in the external word; provided always that the channel in which the water flows, and out of which we may freely drink, does not prevent us from paying due honor to the fountain.