And now there is another reason we must extend this teaching a bit further. It is, as I have already said, that, seeing that men are created in the image of God and that their souls have been redeemed by the blood of Jesus Christ, we must try in every way available to us to draw them to the knowledge of the gospel.
– John Calvin, Sermons on Acts 1-7, Sermon 41, Acts 7:51, p., 593.
Yet sometimes he also causes those whom he illumines only for a time to partake of [grace]; then he justly forsakes them on account of their ungratefulness and strikes them with even greater blindness.
– Institutes of Christian Religion, 3.24.8.