Calvinism as a system claims that God reprobated a large segment of mankind so that they can never be saved.  It further claims that the atonement is for this reason limited only to the elect who alone will benefit from the atonement and be saved (with no possibility of falling away). In such a system Jesus died only for the sins of the elect. If this is the case it seems that many passages of Scripture are disingenuous in commanding all people everywhere to repent and believe on Christ when repentance is impossible for reprobates and Christ did not die for them anyway (For more on that see here).
If Calvinism is to be consistent in these claims it cannot allow for a person to rightly tell someone that Christ died for them. The best one can do is say that if they repent and believe, Christ died for them  or that Christ died for sinners (meaning “some sinners” but not necessarily the sinner they are presently speaking to) or that Christ might have died for them, or something similar . Therefore, consistent Calvinists say it is wrong to tell the unsaved that Christ died for them . This may seem shocking enough to most Christians, but Calvinists today are often claiming further that the Bible never gives us an example of anyone telling unbelievers that Christ died for them. It is with this claim in mind that we turn to our text:
1CO 15:1 Now I make known to you, brethren, the gospel which I preached to you, which also you received, in which also you stand,
1CO 15:2 by which also you are saved, if you hold fast the word which I preached to you, unless you believed in vain.
1CO 15:3 For I delivered to you as of first importance what I also received, that Christ died for our sins according to the Scriptures,
1CO 15:4 and that He was buried, and that He was raised on the third day according to the Scriptures, (NASB, emphasis mine)
Paul is recounting to the Corinthians the content of the gospel message as Paul first preached it to them. The need for this reminder is made clearer later in the chapter where we discover that some are denying the resurrection and by extension are denying the gospel that Paul preached. Paul makes it clear that the message as he describes it here is the message he first brought to them “of first importance”. This gospel message includes three main components. The first is that “Christ died for our sins” followed by the fact that Christ was buried and then rose again on the third day, all of which happened “according to the Scriptures”. This is the specific content of the gospel message as Paul first delivered it to these Corinthians. They “received” this gospel by faith and are currently standing on these truths delivered to them by Paul when he first preached this specific gospel message to them.
We can draw several conclusions from what Paul says to the Corinthians in this passage. The one that most concerns us at present is that the initial message of the gospel to the Corinthians prior to their receiving (by faith) the message Paul preached is that “Christ died for our sins according to the Scriptures”. The rest of the gospel message about the resurrection reinforces this central truth. We know this because Paul later explains to them that if Christ is not raised then their faith is worthless and they are “still in [their] sins” as a result. Therefore, the central message of the gospel, according to Paul, is that “Christ died for our sins”. The resurrection is no less important in that it gives ultimate verification to the primary message of the gospel, Christ’s death for the forgiveness of sins.
But does Paul say that Christ died only for the sins of the elect? To the contrary, Paul’s initial message to these unsaved Corinthians was that “Christ died for our sins.” The natural way to understand Paul’s language here is that Christ died not only for Paul’s sins, but for all of their sins as well. This is the message they needed to receive in order to be saved. In accepting the truth by faith that Christ died for their sins, they received the forgiveness that results from Christ’s death to all that believe. So here we have a clear example of the gospel message being preached to unbelievers and the central message of that gospel being not that Christ died for the elect, or that Christ died for sinners (meaning “some” sinners), but that Christ died for “our” (everyone’s) sins. This is, according to Paul’s own words, the content of the gospel message delivered to them “as first importance.” Paul is now admonishing them to remember that message that they received (that Christ died for them) and to continue to stand on that message, less their faith prove to be “in vain”. But if it is unclear whether Christ died for them, how then can they be called on to stand firm on that truth?
Suppose we take Paul’s words to mean Christ died for “our” (the elect’s) sins . That would be a most unnatural way to read the text. Beyond that, it is hard to imagine how they would appropriate that message. Is it by believing that Christ died for the elect alone that they are saved? Surely not. They could believe that Christ died for Paul and others that at least appeared to be elect (see note #3 below) without believing that Christ died for them in particular. Indeed, according to Calvinism there is no way to know if Christ died for us until we repent and believe (and even then we cannot know for sure that Christ died for our sins until we persevere to the end [death or Christ’s return] in faith, see note #4 below).
But believe what? According to Paul it is that Christ died for our sins. That is the preeminent message of the gospel and it is a message that is grossly at odds with the claims of Calvinism . We can’t trust Christ to save us if Christ did not die for our sins . We can only trust that Christ might have died for us, though the odds are against it (see note #1 below)
We will now take a moment to examine the first part of Paul’s message as it has further relevance for Calvinism in that it seems to plainly contradict the Calvinist doctrine of inevitable perseverance:
1CO 15:1 Now I make known to you, brethren, the gospel which I preached to you, which also you received, in which also you stand,
1CO 15:2 by which also you are saved, if you hold fast the word which I preached to you, unless you believed in vain. (NASB, emphasis mine)
In verse one Paul makes it clear that he is addressing those who received his initial gospel message that Christ died for their sins and was buried and raised again. Not only did they receive this message, but they are presently standing on that message and as a result will be finally saved, with one important qualifier: they must continue to hold on to that truth in the faith that they initially received that truth in. In other words, if they turn from the truth of that initial message that they received and deny the resurrection, they would in turn be denying the very truth that will ultimately save them. In such a case their initial faith in the death and resurrection of Christ will prove to have been in vain, since it did not continue.
This is problematic for Calvinism in two important ways. First, Calvinism asserts that true faith will always endure because God will preserve that faith and cause the believer to persevere in that faith Himself. So if one receives the truth of the gospel and stands on that truth he will certainly continue to stand on that truth to the end. If one does not continue he never really stood on that truth to begin with and never truly received that truth to begin with. But this is at odds with the way Paul speaks of the matter. Paul does not doubt they received the message; nor does Paul doubt their present commitment to the message. Paul only questions whether they will continue in that message or turn aside to deny the resurrection, an indispensable part of the message initially received.
If Paul believed that those who fall away never believed in the first place we would expect him to end with “unless (otherwise) you never really believed to begin with” or something similar. But instead Paul simply points to the fact that in abandoning the faith one will not attain to the object and hope of that faith once exercised since he has turned away from the very message that will ultimately save him. Therefore, their faith, while it truly existed for a time, will prove to be “in vain” since it does not continue to the point of fully receiving the promise of the gospel- final salvation.
We see similar language in Romans 11:16-24. After describing election in the context of the ancient olive tree (which represents God’s covenant people beginning with their identity with the patriarchs and ending with their identity with Christ, the final and supreme Head of the covenant), Paul goes on to warn the Gentiles who have entered the new covenant through faith in Christ and have been grafted into the people of God as a result, that they must be careful not to be arrogant over the Jews who have been broken off from the olive tree as a result of their rejection of Christ, the final and supreme Head of the covenant. The problem for Calvinism is that Paul describes these Gentiles as believers who have been grafted into God’s chosen people and who are presently standing by faith. There can therefore be no doubt that Paul is speaking to saved individuals who are presently enjoying the blessing of the new covenant through faith union with Christ. The specific language makes this indisputable,
Ro 11:17 If some of the branches have been broken off, and you, though a wild olive shoot, have been grafted in among the others and now share in the nourishing sap from the olive root,
Ro 11:18 do not boast over those branches. If you do, consider this: You do not support the root, but the root supports you.
Ro 11:19 You will say then, “Branches were broken off so that I could be grafted in.”
Ro 11:20 Granted. But they were broken off because of unbelief, and you stand by faith. Do not be arrogant, but be afraid.
Ro 11:21 For if God did not spare the natural branches, he will not spare you either.
Ro 11:22 Consider therefore the kindness and sternness of God: sternness to those who fell, but kindness to you, provided that you continue in his kindness. Otherwise, you also will be cut off.
Just as in 1 Corinthians 15 we find Paul telling those that he describes as presently saved and enjoying the benefits of salvation that they can yet be “broken off” from the people of God and the salvation that belongs to them alone if they do not “continue” in God’s kindness through faith. Again, if the Calvinist accounting of perseverance were true, we would expect to find Paul telling them that they would have never been in the olive tree and have never believed in the first place. However, Paul says exactly the opposite; describing them as true believers who can be broken off from a tree they are presently attached to, enjoying all the benefits of God’s elect people in Christ Jesus. 
Conclusion: We have found that Calvinist claims about limited atonement and inevitable perseverance are severely challenged by the language of 1 Corinthians 15. We have also found that the Calvinist claim that it is unscriptural to tell sinners that Christ died for their sins is inaccurate, as we have Biblical precedent in Paul’s initial gospel proclamation to the Corinthians that “Christ died for our sins.” We have also examined a few possible counter arguments and found them to be severely problematic given the context and specific language employed by Paul in 1 Corinthians 15.
 If Jesus is correct that “few” in contrast to “many” enter through the narrow gate unto salvation (and I assume Calvinists would agree that He is correct), then we must conclude that God has reprobated the vast majority of humanity “for His glory” (Matthew 7:13, 14). Somehow, it would then seem that reprobation must bring God more glory than election unto salvation. It should also be noted that when I speak of God reprobating people, it could be conceived as a direct action of God or as a more indirect action, as in “passing over” the many that will as a result be left reprobate. I agree with Wesley and many others that this amounts to a distinction without a difference, or as John Wesley notes after carefully dissecting the claims that passing over is very different and less offensive than direct reprobation, it is “the self same thing.” (See Wesley’s famous sermons, Predestination Calmly Considered and On Predestination).
 This would probably seem to most to be the inverse of what the Bible claims and what we should tell unbelievers about the Gospel- that because Christ died for them, they should repent and believe. Peter actually says exactly that in his second sermon in the book of Acts (For a more detailed study of that passage see here).
 In such a scheme Calvinist parents can have no real assurance that Christ died for any of their children or that God even loves their children in a saving way (God may instead “hate” them in reprobation as He did Esau). Nor can a Calvinist parent tell their children that Christ died for them or that God loves them in any meaningful way. Calvinist Erwin Lutzer tries to claim that Calvinists can have strong assurance that their children are elect, but that claim is easily refuted given the fundamental premises of Calvinism (for more on that see here).
 But really it is unclear how a Calvinist could even tell someone who appears to be a saved believer that Christ died for them as they may yet fall away and, by Calvinist assumptions, prove that they were never saved or elect to begin with. Calvinism severely undercuts Biblical assurance in many ways (for more on that see here).
 Another possible Calvinist explanation would be to claim that Paul was speaking of them as they presently were in saying that Christ died for “our sins” since upon their believing Paul could now say that Christ had in fact died for them. But this would be an extremely awkward way to understand the text since Paul is recounting his initial message to them and admonishing them to continue to believe it as they first received it. Not only that, but as noted above, even if they appeared to believe, Paul could not say with confidence, according to Calvinism, that Christ died for them until they demonstrated their faith was genuine and saving by persevering to the end. But isn’t it true that even in Arminianism many might not have genuine saving faith? Indeed it is, but that would not change the fact that Christ died for them since in Arminianism Christ died for all, even those who will never believe. So Arminianism would still be fully in harmony with Paul’s gospel message.
 Again, we find the same basic gospel message in Peter’s second sermon recorded in Acts 3. For details concerning that message see my post, Provisional Atonement Part 3: The Integrity and Justice of God in the Gospel Offer. But even if the Bible nowhere showed anyone preaching the message that “Christ died for your sins” it is everywhere implied, especially in those passages which command all to repent and believe on the message on the basis of Christ’s death along with those passages which use universal language in describing the extent of the atonement, of God’s love or desire for all to be saved. There are many things that believers speak about in ways that the Bible never directly does. For example, the Bible nowhere describes the Trinity as we often explain it to those who have questions about the Trinity (as God in three persons, or One eternal Being existing in three persons, etc.). However, we can confidently say such things based on what the Bible does say, even if the Bible does not use that specific language.
Furthermore, the Bible only records a few accounts of the gospel message being preached to sinners and we should not assume that there were not many other ways the message was articulated in the hundreds or thousands of other times the gospel was preached to unbelievers. And thankfully, we have in 1 Cor. 15 clear evidence that Paul indeed preached to unbelievers that Christ died for their sins (since, in that context, “ours” naturally includes “yours” as well as “mine”).
 A Calvinist could possibly answer this by pointing out that in Calvinism God must cause us to have faith irresistibly and would only cause those that Christ died for to believe that Christ died for them. But this still does not address the resulting disingenuous nature of the offer of salvation throughout Scripture or the specific language that Paul used in presenting the gospel message to the Corinthians as recounted in 1 Corinthians 15; neither does it address the difficulty inherent in the fact that only a faith which perseveres to the end can be considered genuine in Calvinism (see note #4 above). There again, the Calvinist has no solid grounds for believing that Christ died for them at all since he may yet fall away and prove that his faith was not genuine after all and that Christ did not die for him, though he thought he did. Only the Arminian view allows for us to accept the straightforward language in Scripture concerning the gospel offer and the nature of the gospel to be received, that Christ died for all and there is therefore forgiveness of sins available for all (Acts 3:19-26).
 We should further point out that if Paul’s warning to these believers can never attain or actually happen since God will inevitably preserve them in the faith, then it is nonsense for Paul to tell them to “be afraid” lest they are broken off as a result of not continuing in the faith. Paul speaks to them as true believers joined to God’s elect people and for that reason, according to Calvinism, they have nothing to fear since it is impossible for true believers to fall away. Everything in Paul’s language points us towards the real possibility of apostasy and away from the Calvinist doctrine of inevitable perseverance. For a detailed study of several Scriptures which contradict the Calvinist doctrine of inevitable perseverance, see my series here.