The gospel message of Jesus Christ rests upon two indisputable facts, the death of Jesus Christ as propitiation for our sins, and the bodily resurrection of Jesus Christ. If Christ did not rise, then His death had no meaning. It would mean that Jesus was not the Son of God, that He was instead just another man.
It is because Christ rose from the dead that you and I know that He conquered death forever and that we can have eternal live with Him if we make Him our Savior. The work of our salvation was completed when Jesus Christ came out of that tomb.
Listen as Paul describes the proof of the resurrection of Jesus Christ in this verse-by-verse study of 1 Cor. 15:5-11.