The Gospel is not complete without proclaiming Jesus’ resurrection.
When Paul wrote to the Corinthians, he gave a concise statement of the message which saves. Some have called it “the Gospel in a nutshell.”
This is found in (1 Corinthians 15:1-4 ESV) “Now I would remind you, brothers, of the gospel I preached to you, which you received, in which you stand,  and by which you are being saved, if you hold fast to the word I preached to you—unless you believed in vain.  For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures,  that he was buried, that he was raised on the third day in accordance with the Scriptures…”
Jesus’ resurrection gives us the ability to believe in Him, to trust who He is and what He accomplished for us through His suffering death on the cross. We must come to know Jesus rose again. Knowing this, we turn from our sin and from trusting anything else, to trusting in Him alone as the one worthy to lay down His own life for our redemption. And just as He rose from the grave, we are given new life after having been dead in our sins. We are now learning to know God and to walk with Him. Because of our Savior we have now escaped the judgment for our sin which Jesus called being “sentenced to hell” (Mt.23:33 ESV). We have been given the gift of eternal life with our loving God.
Paul mentions the importance of fully believing the truth of the resurrection when he writes to the Romans: (Romans 10:8-11 ESV) “But what does it say? “The word is near you, in your mouth and in your heart” (that is, the word of faith that we proclaim);  because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved.  For with the heart one believes and is justified, and with the mouth one confesses and is saved.  For the Scripture says, “Everyone who believes in him will not be put to shame.”
One could confess with the mouth, not believing, and it would mean nothing at all. But one who believes also confesses with the mouth. The phrase used in the first passage above, “if you hold fast,” is important to understand. Holding fast, and even confessing, does not save us. God saves us through the truth, and the resurrection is a vital, indispensable part of the truth. We “hold fast” because we do truly believe and have been brought out of our sins to this new life.
We want to be sure we are proclaiming Jesus’ resurrection and demonstrating its truth with our lives!