The Christian faith is built upon Jesus' resurrection from the dead. Paul stated that "if Christ is not risen, then [the apostles'] preaching is vain and your faith is also vain" (I Cor. 15:14). The reason for this is twofold: 1) the remission of sins comes as a result of, and in accordance with, Christ's resurrection, and 2) unless Christ arose from the grave, there is no hope of life/reward after death (I Cor. 15:17,18).
In order for an individual's sins to be forgiven, he/she must emulate the death and resurrection of Jesus Christ. This is why Paul said that "we were buried with [Christ] through baptism into death, that just as Christ was raised from the dead...even so we also should walk in newness of life" (Rom. 6:4). What could that newness of life be but a life freed from sin (Ac. 2:38)? A moment spent in the grave of baptism, therefore, frees us from the chains of sin and death, and gives us life anew--a life with Christ (Gal. 3:27).
Finally, Christ's victory over the power of death ensures us that there is coming a day when "the dead in Christ shall rise first," (I Thess. 4:16) and all the deceased of humanity after them. They (perhaps, we shall be among them) shall all rise for one reason— "to receive the things done in the body, according to what [they have] done, whether good or bad" (II Cor. 5:10). None of us shall escape that day. Are you ready for that day to come?