Prevenient Grace is Way Better than Irresistible Grace
I am not going to use the Scriptures here because Calvinists will just insert whatever they want into any verse, so providing Scripture will not help the Calvinist usually as they have already made up their mind. Instead I would like to try another approach. It's clear we can't prevent the Calvinist from seeing their mistaken assumption of inserting instead of not assuming anything, so let's try another approach to lead the Calvinist to Christ (almost all Calvinists are unsaved and going to Hell but a few may one day have a change of mind). Nor will I appeal to the conscience of a Calvinist because it is seared as hard as the Pharaoh's.
Prevenient grace refers to God's grace being sufficient for everyone to have the choice. Even though Adam fell and everyone is born into sin, by the age of accountability they have been given sufficient grace to be able to freely respond to the gospel message. Even those who have never heard of the gospel of salvation in Christ likewise have received sufficient common grace that ultimately becomes summed up in Christ to accept Christ if presented the word of God.
Because God's grace is abundant and the precious blood of Christ atones for sins, the salvation of the cross by the Holy Spirit is perfect.
Recall I said I would not appeal to Scripture because the Calvinist will just insert whatever and nor will I appeal to their conscience because it is cold as stone. Instead let us try appealing to pure logic alone!
God has infinite foreknowledge that we agree, but if God can provide sufficient grace to everyone to have the choice then that would be better than having to irresistibly regenerate someone without given them the choice since God is relational. Therefore, God decrees (provisions) by foreknowing all available choices and our free-choice because God exists outside of time, e.g. Jesus was not always a man as Matt Slick thinks. And a person doesn't go to Hell simply because they were born into sin, e.g. Matt Slick believes they do.
The Calvinist gets troubled in his head because he wants to know why one person chooses one way and another chooses another. That is the nature of free will to have the choice. The mechanism by which God gives us this ability may never be understood like there are many things God knows that we might never know such as how God reconciles His infinite foreknowledge with free will. If I were to appeal to your conscience I would simply say this is the beginning of humility to humbly accept this fact.
But because the Calvinist does not get an answer from God they create the cult of Calvinism that answers that question immorally; hence, they enter into a counterfeit salvation from a false Christ. This is why Calvinists are going to Hell, for they do not genuinely receive the Lord Jesus as Savior having replaced Him with another. They reject the God of prevenient grace.
My prayer is maybe in some small measure, not necessarily immediately but over time, these words will help lead the Calvinist to Christ. Thank you Jesus! Amen.
