The Importance of the Resurrection to Christianity
The Resurrection refers to the belief that Christ arose from the dead three days after his crucifixion. Unarguably, Christ's resurrection is the single most important event in the history of Christianity. In fact, much of Christianity is based on this belief, as is seen through the sacrament of Communion. Through his death, Christ atoned for the sins of all mankind. Through Christ's resurrection, every Christian that ever existed, or may exist in the future, has the opportunity to gain redemption, as Christ himself was redeemed. If it was not for Christ's resurrection, people would likely see him as just another prophet seeking glorification.
The new covenant
The Bible speaks of a new covenant with God through which Christ is the mediator. This new covenant promises the forgiveness of sins and eternal redemption through Christ's sacrifice, that is, through his willingness to die for the sins of mankind. At the last supper with his disciples, Christ refers to the wine as the new covenant in his blood and has his disciples drink it. In this way, they share in the spilling of Christ's blood but also in his resurrection and redemption.
Why do Christians believe that Christ was resurrected?
As with most tenets of Christianity, the belief that Christ resurrected stems from Scriptures. The New Testament describes how he disappeared from his tomb after three days and was subsequently seen by a number of apostles and other people for days afterward when he ascended into heaven. The day of Christ's resurrection is Easter Sunday, the holiest of all Christian holidays.
A firm belief in the resurrection of Christ is a matter of faith, not of scientific proof. The sinful ways of mankind began with the fall of Adam and Eve, but not until the advent of Christ's new covenant was all mankind elected to be saved. Through his death, Christ took on the weight of all mankind's sins and through his resurrection, he absolved all mankind of sin and, through their free will, granted them the power to follow his teachings and share eternal life with him in heaven.