Only a risen Jesus proves His power over sin and death. Only a risen Jesus can offer us forgiveness and new, eternal life with God!
Now I would remind you, brothers and sisters, of the good news that I proclaimed to you, which you in turn received, in which also you stand, through which also you are being saved, if you hold firmly to the message that I proclaimed to you—unless you have come to believe in vain. For I handed on to you as of first importance what I in turn had received: that Christ died for our sins in accordance with the scriptures, and that he was buried, and that he was raised on the third day in accordance with the scriptures, and that he appeared to Cephas, then to the twelve. Then he appeared to more than five hundred brothers and sisters at one time, most of whom are still alive, though some have died. Then he appeared to James, then to all the apostles. Last of all, as to one untimely born, he appeared also to me. For I am the least of the apostles, unfit to be called an apostle, because I persecuted the church of God. But by the grace of God I am what I am, and his grace toward me has not been in vain. On the contrary, I worked harder than any of them—though it was not I, but the grace of God that is with me.
Whether then it was I or they, so we proclaim and so you have come to believe.
Now if Christ is proclaimed as raised from the dead, how can some of you say there is no resurrection of the dead? If there is no resurrection of the dead, then Christ has not been raised; and if Christ has not been raised, then our proclamation has been in vain and your faith has been in vain. We are even found to be misrepresenting God, because we testified of God that he raised Christ—whom he did not raise if it is true that the dead are not raised. For if the dead are not raised, then Christ has not been raised. If Christ has not been raised, your faith is futile and you are still in your sins. Then those also who have died in Christ have perished. If for this life only we have hoped in Christ, we are of all people most to be pitied.
But in fact Christ has been raised from the dead, the first fruits of those who have died. (1 Corinthians 15:1-20)