I enjoy the below definitions not only because of their theological correctness but also because of the beauty and poetry of the words. The gospel is good news indeed!
In no particular order:
At its briefest, the gospel is a discourse about Christ, that he is the Son of God and became man for us, that he died and was raised, and that he has been established as Lord over all things…The gospel is a story about Christ, God’s and David’s son, who died and was raised, and is established as Lord. This is the gospel in a nutshell.
The good and true story that Jesus has defeated sin, death, and evil through his own death and resurrection and is making all things new, even us. This definition recognizes that the gospel is both narrative and proposition; it is focused on Jesus not us or our works; it is anchored in history through Jesus death and resurrection; it is keeps Jesus identity as both a sovereign Lord and a redeeming Christ; finally, it reminds us of the scope of the gospel, that it is as big as new creation and as small as you and me.
The good news that Jesus Christ came from heaven, died on the cross having lived a perfect sinless life, bore then in His body the full penalty of our sins, was raised from the dead. Those who repent of sin and place their faith in the perfect work of Christ can and will be saved. There’s the gospel.
The gospel is the proclamation of Jesus, in [two] senses. It is the proclamation announced by Jesus – the arrival of God’s realm of possibility (his “kingdom”) in the midst of human structures of possibility. But it is also the proclamation about Jesus – the good news that in dying and rising, Jesus has made the kingdom he proclaimed available to us.
The gospel is to announce that the Story of Jesus, who is Messiah/King, Lord and Savior, fulfills or completes the Story of Israel. It is the good news that God’s promises have now been realized in Jesus Messiah, Lord and Savior.
The ‘gospel’ is the good news that through Christ the power of God’s kingdom has entered history to renew the whole world. When we believe and rely on Jesus’ work and record (rather than ours) for our relationship to God, that kingdom power comes upon us and begins to work through us.
The Gospel is the good news of our final and full enjoyment of the glory of God in the face of Christ. That this enjoyment had to be purchased for sinners at the cost of Christ’s life makes his glory shine all the more brightly. And that this enjoyment is a free and unmerited gift makes it shine more brightly still. But the price Jesus paid for the gift and the unmerited freedom of the gift are not the gift. The gift is Christ himself as the glorious image of God – seen and savored with everlasting joy.
The good news of the Gospel is that Jesus lived a life of perfect righteousness, of perfect obedience to God, not for His own well being but for His people. He has done for me what I couldn’t possibly do for myself. But not only has He lived that life of perfect obedience, He offered Himself as a perfect sacrifice to satisfy the justice and the righteousness of God.
The gospel is the good news that God, who is more holy than we can imagine, looked upon with compassion, people, who are more sinful than we would possibly admit, and sent Jesus into history to establish his Kingdom and reconcile people and the world to himself. Jesus, whose love is more extravagant than we can measure, came to sacrificially die for us so that, by His death and resurrection, we might gain through His grace what the Bible defines as new and eternal life.
Matt Chandler, Josh Patterson, and Eric Geiger:
In its simplest form, the gospel is God’s reconciling work in Christ – that through the life, death, and resurrection of Christ, God is making all things new both personally for those who repent and believe, and cosmically as He redeems culture and creation from its subjection to futility.