Jesus is not rotting in a tomb somewhere. He died, but rose from the grave and is alive, seated with God the Father in Heaven. He is awaiting the proper time to return and set all things right once more. Many have come with great teachings and amazing claims, but none has authenticated those things by conquering death. Jesus Christ stands alone in that regard.
The Resurrection of Jesus is a central focus of Christianity. Paul says here that without it, everything crumbles and Christianity is a waste of time. With it however, everything changes - our lives are changed, our purpose is changed, our future is changed. Everything hinges on the Resurrection of Jesus. In fact, Paul says that the essentials of the Gospel are that Jesus died for our sins, that he was buried, and that he was raised on the third day.
The Resurrection is not just a claim. Jesus clearly demonstrated it by His activities following the crucifixion. We are not left with an empty tomb and a lot of conjecture as to how it became empty. Instead, Jesus told us ahead of time what would happen. Then, He appeared to hundreds of people after He arose to attest to His life and prove that what He had said had taken place. At the time of Paul's writing, many of the witnesses' to this fact could be interviewed and questioned. Now, with evidence that Jesus claimed to be God and demonstrated it by fulfilling the Scriptures, rising from death, and ascending to Heaven, things are different.
Paul says that our lives change when we believe the gospel. We are saved. Our lives are changed. Our past is forgiven. We are given life in the present, but we are also promised life in the future. No longer are we required to fix our problems, overcome our troubles, or make things happen. Instead, God gives us His grace and His grace is sufficient for whatever we encounter in life (2 Cor. 12:9).
Paul's life dramatically changed when he understood it. He said, "But by the grace of God I am what I am, and his grace to me was not without effect. No, I worked harder than all of them - yet not I, but the grace of God that was with me." The grace of God is always effective, changing the hardest of hearts and overcoming the greatest of obstacles. The Resurrection demonstrates that. Death and the grave are the greatest obstacles we face and Jesus has already secured victory over these enemies. He has assured us that we can give ourselves fully to the Lord, knowing that He will be all that we need and can overcome whatever we may face. We are to throw ourselves fully into following Him, but it is His grace that makes the difference. The Resurrection promises us that we can give ourselves fully to the Lord and know that He will give us life in return.
The Resurrection gives us hope for more than today, however. It also points us to a future when all things will be made right. All the destruction that our sin has wrought will be undone. Everything will be made perfect and right, just as God intended. Our weak and failing bodies will be transformed. The earth will be made new. Victory will be achieved. The Resurrection offers this promise. The promise that its not futile or a waste of time, but that God is in control and He will restore it all once again.