We have already been told that hardening is not less under the immediate hand of God than mercy. Paul does not, after the example of those whom I have mentioned, labour anxiously to defend God, by calling in the aid of falsehood; he only reminds us that it is unlawful for the creature to quarrel with its Creator. --John Calvin


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If man's nature is not ONE of the determinate causes of man's choices then man is not responsible for anything he does. This is the Arminian/semi-Pelagian argument used all too often against Calvinism, for IF everything that a man thinks, feels and does is totally caused by God's eternal decree, man becomes the proverbial puppet.

Calvin answered your objection clearly. You seem to be more afraid of the Arminians than of God:

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1. The human mind, when it hears this doctrine, cannot restrain its petulance, but boils and rages as if aroused by the sound of a trumpet. Many professing a desire to defend the Deity from an invidious charge admit the doctrine of election, but deny that any one is reprobated (Bernard. in Die Ascensionis, Serm. 2). This they do ignorantly and childishly since there could be no election without its opposite reprobation. God is said to set apart those whom he adopts for salvation. It were most absurd to say, that he admits others fortuitously, or that they by their industry acquire what election alone confers on a few. Those, therefore, whom God passes by he reprobates, and that for no other cause but because he is pleased to exclude them from the inheritance which he predestines to his children. Nor is it possible to tolerate the petulance of men, in refusing to be restrained by the word of God, in regard to his incomprehensible counsel, which even angels adore. We have already been told that hardening is not less under the immediate hand of God than mercy. Paul does not, after the example of those whom I have mentioned, labour anxiously to defend God, by calling in the aid of falsehood; he only reminds us that it is unlawful for the creature to quarrel with its Creator. Then how will those who refuse to admit that any are reprobated by God explain the following words of Christ? “Every plant which my heavenly Father has not planted shall be rooted up,” ( [Mt. 15:13] ). They are plainly told that all whom the heavenly Father has not been pleased to plant as sacred trees in his garden, are doomed and devoted to destruction. If they deny that this is a sign of reprobation, there is nothing, however clear, that, can be proved to them. But if they will still murmur, let us in the soberness of faith rest contented with the admonition of Paul, that it can be no ground of complaint that God, “willing to show his wrath, and to make his power known, endured with much long-suffering the vessels of wrath fitted for destruction: and that he might make known the riches of his glory on the vessels of mercy, which he had store prepared unto glory,” ( [Rom. 9:22, 23] ). Let my readers observe that Paul, to cut off all handle for murmuring and detraction, attributes supreme sovereignty to the wrath and power of God; for it were unjust that those profound judgments, which transcend all our powers of discernment, should be subjected to our calculation. Institutes of the Christian Religion, Book 3, Chapter 23, Section 1


For "who has known the mind of the LORD that he may instruct Him?" But we have the mind of Christ. (1 Corinthians 2:16 NKJ)