Institutes of the Christian Religion by John Calvin.

Book 2: Of the knowledge of God the Redeemer, in Christ, as first manifested to the fathers, under the law, and thereafter to us under the gospel.

Chapter 3: “Everything Proceeding From The Corrupt Nature of Man Damnable.”

Section 10: When our will moves us, we cannot choose to obey or resist it, but it pushes us until the end result is achieved. This is not the idea that God merely offers aid and we choose to accept it, but that God drives toward the goal of salvation despite our desire against it. If it were left to us, no one would ever be saved – our fallen natures would prohibit it. “The Apostle’s doctrine is not, that the grace of a good will is offered to us if we will accept of it, but that God himself is pleased so to work in us as to guide, turn, and govern our heart by his Spirit, and reign in it as his own possession. Ezekiel promises that a new spirit will be given to the elect, not merely that they may be able to walk in his precepts, but that they may really walk in them (Ezek. 11:19; 36:27).” Everyone who is led by God to salvation, is saved, and cannot be broken free from this salvation. Augustine goes further, stating, “How came you? By believing. Fear, lest by arrogating to yourself the merit of finding the right way, you perish from the right way. I came, you say, by free choice, came by my own will. Why do you boast? Would you know that even this was given you? Hear Christ exclaiming, ‘No man comets unto me, except the Father which has sent me draw him.’” Jesus clearly refutes those who refuse to believe in predestination or election, when He states in John 6:44, “No one can come to me unless the Father who sent me draws him.”

Section 11: Those who refute the idea of the eternal perseverance of the saints, have lost the battle before they even began to fight. If our salvation is orchestrated by God, as we have already shown so clearly, and if God has promised to hold us to Him, after replacing our hearts and converting our will, then it is impossible for us to fall away as it is our sovereign Creator who holds us fast to Him. Scripture defends this in Philippians 2:13 where Paul states, “it is God who works in you, both to will and to work for his good pleasure.” If God is the one who works in us to His own good pleasure, then how can we fall away, even when we do sin. Our sin has been paid for by our Creator. We do not “co-operate” in our salvation by any means. If we did, we would not be able to hold ourselves to Him who saved us. “If it is meant that after we are once subdued by the power of the Lord to the obedience of righteousness, we proceed voluntarily, and are inclined to follow the movement of grace, I have nothing to object. For it is most certain, that where the grace of God reigns, there is also this readiness to obey. And whence this readiness, but just that the Spirit of God being everywhere consistent with himself, after first begetting a principle of obedience, cherishes and strengthens it for perseverance? If, again, it is meant that man is able of himself to be a fellow-labourer with the grace of God, I hold it to be a most pestilential delusion.”