Many consider the Christian message (CM) irrelevant. Frankly, much of what passes for the CM is irrelevant, boring, and trivial. “Be a nice person” (who doesn’t know that?). “God loves you and has a wonderful plan for your life” (well, then, we’re all fine). “Have a purpose-driven life” (I’d rather have fun). “You can have your best life now” (it’s not so bad already, yawn).
Moralism, universalism, “purpose-ism,” health and wealth—these are not the CM. Part of the problem is that people don’t even know what the CM is. How then can they reasonably consider it irrelevant?
Nothing could be more relevant to you than the biblical CM. That is because of the nature (divine, practical, consequential) and truth (historical, verifiable) of the CM. That message is not fundamentally an ideal, an agenda, a challenge, or even a comfort. It is news, reporting something that actually happened, something so supremely wonderful that above all other news it deserves to be called the Good News, Gospel, Evangel (Gk.), Bona Annuntiatio (Lat.).
Strictly speaking, what you do with it is not part of the Gospel. The Gospel is about what God has done already. It proves the best news of all to those who believe it, and the worst possible news to those who persist in unreasonable skepticism. Ultimately, no neutrality is possible. This is the all-important news that divides all humanity into two groups: those getting better and getting worse, and ultimately, the eternally redeemed and the eternally ruined.
This Gospel is succinctly stated in 1 Cor 15.3b-5a. 1 It’s all about Christ. 2 It’s all about His mission accomplished. 3 It’s all about two events and their proof (died/buried; risen/seen). 4 It’s all about the biblical interpretation of those events (atoning sacrifice, prophetic realization). 5 It is a divine revelation to be proclaimed, not someone’s opinion to be debated. 6 It has the most profound implications for your life and your future. 7 It includes the one miracle in human history that matters most—more than all other miracles actual and alleged, and most to you personally and objectively, whether believe it or not.
Everything ultimately hinges on the resurrection of Christ. If our preaching of it is false, Christians are “of all men most miserable,” “most to be pitied.” If it’s true, then things are totally reversed. Christianity is either fundamentally true or false. If it’s true, then you must believe as a Christian, live as a Christian, and die as a Christian. If it’s false, then don’t speak well of us Christians. We’re frauds.
Now consider the impeccable logic of 1 Cor 15.12-23 (read).
AT THE CROSSROADS (v. 12)
“If” is not hypothetical but sets up the next premise to be considered. The apostolic proclamation of Christ’s resurrection is a fact. So then, “How can some of you say that there is no resurrection of the dead?” We infer that some in the Corinth church, perhaps only a few, were saying this very thing. Their exact teaching is hard if not impossible to ascertain, but
Most commentators believe that few if any denied the resurrection of Christ; but some failed to follow through the eschatological and ethical entailments of what it meant to share in Christ’s resurrection (NIGTC).
How could anyone in the Christian church deny resurrection? It is outrageous but still occurring (e.g., hyperpreterism: resurrection is past only, 70 A.D.).
“Resurrection” here is not just a return to life physically like Lazarus who died again (John 12). Here it is bodily resurrection to eternal immortality, the complete redemption of the body for life in the new creation. So far, only Christ has been raised like this, but His guarantees others’.
“How can you say that?” evokes deeper consideration of the implications.
IF THERE IS NO RESURRECTION (vv. 13-19)
1. Then Christ Is Not Raised (vv. 13, 16). Evidently this goes beyond what the false teachers within the church were saying, but it necessarily follows, though they would have been loath to admit it. Not only Christ did not rise from the dead, but “Christ is not risen,” i.e., immortal now. The grammar hints “Christ is now and continues to be in the condition of one who was raised from the dead” (Lenski on 15.4), i.e., alive eternally in every sense. This “impossible conclusion” disproves the premise.
2. Then Our Preaching and Your Faith Is Vain (vv. 14, 17). This more obviously follows from the first inference above, since the fundamental CM and faith of Christians is His resurrection. “Vain” means “devoid of intellectual, moral, or spiritual value, empty . . . without any basis, without power” (BAGD). Along with this necessarily comes, “ye (plural) are yet in your sins,” still under wrath facing Judgment Day, our most dire problem.
3. Then the Apostles Are Liars about God (v. 15). “False witnesses” is courtroom language, very serious (9C, Exod 20.16; Prov 19.5, 9), esp. when misrepresenting oneself as spokesman for God (Ezek 13.8-9). Draw a line in the sand! True or false; there is no alternative.
4. Then Deceased Christians Have Perished (v. 18). “Perished” has the strongest adverse sense to be completely lost for ever, the deadest of the dead, lost in the spiritual sense (trans., commentaries). Without resurrection, their vain faith would have led them to eternal ruin.
5. Then Living Christians Are the Most Pitiable (v. 19). 19a AV: “if in this life only we have hope in Christ,” i.e., that hope is a delusion which proves false in the life to come. Like saying “if Christianity is not the true, saving religion.” 19b: “We are of all men most miserable” (i.e., pitiable) because 1) we have lived a life of hardship, self-denial, suffering, and possible martyrdom, but it was for no reason; 2) disappointed hopes are worse than none; 3) we would sacrifice present enjoyment and lose future eternal life; 4) there is no present forgiveness of sin and no inheritance in heaven; 5) they hope for the restoration of all things in heaven (from Exegetical Summary of 1 Cor 10-16).
BUT CHRIST IS RISEN (vv. 20-23)
V. 20a is a joyful, confident trumpet blast, in contrast with dismal if logical consequences in vv. 13-19 of no resurrection. So what gloriously and logically follows because Christ is risen?
Generally, first turn around every gloomy “then”: 1) Gospel preaching and Christian faith are true, precious, and profitable. 2) The Apostles are true prophets of God with beautiful feet (Isa 52.7; Rom 10.15). 3) Deceased Christians are happy in heaven right now, and with living Christians destined to eternal glory. 4) All Christians are most to be envied for they are the most blessed both here and hereafter.
All this is implied, but Paul continues to elaborate further on the implications of Christ as risen from the dead.
1. Christ Is the Firstfruits of Them That Slept (v. 20b). “Them that slept” refers to those Christians who have died, mentioned in v. 18. “Firstfruits” is an idea steeped in OT thinking and Jewish custom (cf. Prov 3.9-10).
Paul uses here the image of the first sample from a crop. This fruit or grain was offered to God, especially on the day following the Passover sabbath. The first installment of the crop was understood as a symbol of God’s promise and the people’s hope that the rest of the harvest would follow. Thus TEV’s “guarantee” is a good English rendering (UBS Handbook).
Christ’s historic resurrection and His eternal immortality is the guarantee that our Gospel faith is sound and our hope of glory (v. 19) has already been secured and is absolutely certain to be fully realized at last.
Any sensible sinner has to concede that if the CM is true that Jesus is actually, physically, eternally risen, then that changes everything. I.e.,
The resurrection of Christ is the miracle that matters most!
For you, O skeptic, to be wrong about this is to be lost now and forever except you repent! Why would you stake your eternal well-being on the absurd notion that the Bible is a lie from cover to cover, an elaborate fraud, and the entire Christian faith is evil? And evil it must be if it is not true.
Since Christ is risen, non-Christians are the ones whose beliefs are vain, powerless, and lies, and who are perishing, most pitiable, etc.
2. Christ Is the Representative Man Who Saves All His People (vv. 21-22). Paul shows us the correspondence between the way mankind was lost and is saved—through two representative men, Adam and Christ.
“By man came death” 
the fall of man from life to death. Adam on probation for all his posterity descending from him by ordinary generation (i.e. Christ only excepted). “Since” suggests a propriety, a fittingness to the divine plan of salvation. It was also by human means that God saves man, raises him from death to life. God assumed human nature in Christ for the purpose of killing death by death, and triumphing over death by resurrection. “In Adam” and “in Christ” identifies them as the two great representatives of all human beings. In Adam’s fall we sinned all (and were sentenced to death). Likewise, all who are in Christ shall be made alive (spiritual regeneration and physical resurrection).
This salvation of all His chosen people is a consequence of Christ’s resurrection from the dead.
3. All Christ’s People Will Have Resurrection Life at His Return (v. 23).
Contrast and comparison between Christ’s first and second coming. His resurrection occurred in His first; ours will occur in His second (see 1 Thess 4.13-18). We will experience our “glorification,” “a work of transforming power whereby God finally turns us into sinless creatures in deathless bodies” (Packer, Concise Theology, “General Resurrection”).
THAT is why the resurrection of Christ is the miracle that matters most!