Then Jesus said to His disciples, “If anyone wishes to come after Me, he must deny himself, and take up his cross and follow Me. For whoever wishes to save his life will lose it; but whoever loses his life for My sake will find it. Matthew 16:24–25, NASB
The Gospel of our Lord Jesus Christ is a message given to be passed on as “Good News” of the completed work of Christ on behalf of those He came to save. The message is about His incarnation, His perfect life, His death on the cross, His three days and nights in the tomb, and His resurrection. All of these things were attested to by witnesses. The resurrection is the proof that our Lord is God and that the work of the atonement is complete. Those who effectually hear the Gospel, believe it, receive it by grace through faith and repent as they turn to Christ as Lord and Saviour. As is made clear in Ephesians 2:1–10, there is no one is able to do this on their own, God must intervene making then alive in Christ who were once dead in their sins so they could believe and be saved.