Read all of I Corinthians 15 to find the significance of Christ's resurrection in our assurance.
Empty tomb: Matthew 28:6
Resurrected according to Old Testament Scriptures: 1 Corinthians 15:4
Seen of Peter and then with the twelve apostles: 1 Corinthians 15:5
Five hundred eye-witnesses in one gathering: 1 Corinthians 15:6
Many witnessed His ascension: Acts 1:9