Paul had preached the Gospel of Jesus’ resurrection to the Corinthians, and they had responded positively to his preaching. They believed what he had taught them. So Paul has to tell them that if they follow the philosophical mood of their day and deny the resurrection, they must understand that they are then saying that the apostles, including Paul, who came to them with this Gospel were lying about Jesus’ resurrection. Do the Corinthians really want to go to that conclusion?
In verse 17 Paul talks about the futility of their faith. Earlier he spoke of the emptiness of the apostolic preaching. Now he says that if one denies the resurrection, their faith is futile, that is, it does not work. What Paul means by this is clear in verse 17: if there is no resurrection and Christ has therefore not been raised, the Corinthians are still in their sins. Without the resurrection of Christ your sin has not been forgiven.
Why is that? Jesus Christ, when He lived here in the days of His flesh, prophesied that He was going to die for our sin as the sin-bearer, the innocent Lamb of God, and that God in evidence of that, three days later, would raise Him from the dead. This is why Paul can say, as he does towards the end of the fourth chapter of Romans, that Jesus was crucified for our sin and raised again for our justification. The resurrection was proof that God accepted His atonement. Jesus had said that the Father was going to raise Him from the dead after three days. If He said that and it did not happen, Jesus was mistaken. This would then mean that He was not the perfect sacrifice, and therefore could not die on the cross for our sins. Our sin would then still be on us and not punished in Christ.
Sometimes people think in a muddled way. They want to hold to some big central idea of Christianity, but think that it does not make any difference whether you hold to such things as miracles or a literal resurrection. What matters is whether we live good lives in the present. Paul says it does not work that way in Christianity. If God is perfect, you would expect salvation to be perfect, where each part fits together. We do not always understand how, but it does. But you are in great danger when you begin to weed one doctrine out or change its meaning and conclude that it is not necessary to believe it as it is given in Scripture. Paul says that when you do that you no longer have any Christianity.
He says something else in verse 18. If there is no resurrection, then those Christians who have died are still lost in their sins. If Christ has not been raised, not only are Christians still dead in their sins, but so are those Christians who are no longer living. All of those who have gone before have perished.
The last consequence of not believing the resurrection is in verse 19: “If only for this life we have hope in Christ, we are to be pitied more than all men.” As Christians, this path that we are called upon to tread is not always a pleasant one. We set our value on things to come and not on this earth. Instead of piling up treasures here, we pile up treasures in heaven. But if there is no resurrection, there is no heaven. There is no future reward and all we have suffered and given up is for nothing. If that were true, we are to be pitied for following such a ridiculous superstition.
But then we come to verse 20, and Paul says that none of these consequences arising from a Christ who has not been raised is true. That is not the way it really is. You see, if there were not any resurrection, all these terrible things follow. But Christ has indeed been raised from the dead, and the very fact that He is raised from the dead is the proof that we ourselves will be raised if we are joined to Him in saving faith.

