Jesus willingly suffered and died on the cross in our place -- we sinned, He paid our penalty. But Jesus dead in the grave is not the end of the story. He was raised from the dead as the first fruits of the resurrection. This is His promise to us, that those who trust in Him will also be resurrected to eternal life with Him.

1 Corinthians 15
The Resurrection of the Messiah

15 Now I’m making known to you, brothers, the gospel that I proclaimed to you, which you accepted, on which you have taken your stand, 2 and by which you are also being saved if you hold firmly to the message I proclaimed to you—unless, of course, your faith was worthless.

3 For I passed on to you the most important points that I received: The Messiah died for our sins according to the Scriptures, 4 he was buried, he was raised on the third day according to the Scriptures—and is still alive!— 5 and he was seen by Cephas, and then by the Twelve. 6 After that, he was seen by more than 500 brothers at one time, most of whom are still alive, though some have died. 7 Next he was seen by James, then by all the apostles, 8 and finally he was seen by me, as though I were born abnormally late.

9 For I am the least of the apostles and not even fit to be called an apostle because I persecuted God’s church. 10 But by God’s grace I am what I am, and his grace shown to me was not wasted. Instead, I worked harder than all the others—not I, of course, but God’s grace that was with me. 11 So, whether it was I or the others, this is what we preach, and this is what you believed.
The Resurrection of the Dead

12 Now if we preach that the Messiah has been raised from the dead, how can some of you keep claiming there is no resurrection of the dead? 13 If there is no resurrection of the dead, then the Messiah has not been raised, 14 and if the Messiah has not been raised, then our message means nothing and your faith means nothing. 15 In addition, we are found to be false witnesses about God because we testified on God’s behalf that he raised the Messiah—whom he did not raise if in fact it is true that the dead are not raised. 16 For if the dead are not raised, then the Messiah has not been raised, 17 and if the Messiah has not been raised, your faith is worthless and you are still imprisoned by your sins. 18 Yes, even those who have died believing in the Messiah are lost. 19 If we have set our hopes on the Messiah in this life only, we deserve more pity than any other people.

20 But at this moment the Messiah stands risen from the dead, the first one offered in the harvest of those who have died. 21 For since death came through a man, the resurrection of the dead also came through a man. 22 For as in Adam all die, so also in the Messiah will all be made alive. 23 However, this will happen to each person in the proper order: first the Messiah, then those who belong to the Messiah when he comes.