The gospel meaning good news is the one good news and hope for the world that will last. People put their hopes and dreams in all kinds of things. They prove empty in the end, even though on the way they might somehow fill their lives. But the question is with what and with what impact. The gospel itself is the power of God for the salvation of everyone who believes, a salvation that is rooted in the past, active in the present and promised in the future.
The good news simply speaking is Jesus himself. To find the gospel one needs to get a Bible and read the gospel accounts of Matthew, Mark, Luke and John. I might advise reading them in this order: Mark, John, Matthew and Luke, followed by the other of Luke’s writings, Acts, which with the coming of the blessed Holy Spirit in power, tells the story of what happened after Jesus’ coming in his Incarnation, life and ministry, death and resurrection, and ascension with the promise of his return. After that one should read the letters, starting with Paul perhaps in this order: Ephesians, Romans, 1 Thessalonians, 2 Thessalonians, Galatians, Philippians, 1 Corinthians, 2 Corinthians, Colossians, 1 Timothy, 2 Timothy, Titus, Philemon. And then go on to read the rest of the New Testament. Or to keep it simple (which oftentimes works better for me), just start at the beginning of the New Testament, Matthew, and read all the way through to the end, Revelation.
Better advice yet is to start with the Old Testament followed by the New Testament and read the entire Bible through. Although it might be best to read the New first, and then read the entire Bible through afterward. One makes the best sense of the New Testament from understanding something of what preceded it. And so in a sense, the good news or gospel of Christ is as big as the entire Bible, and for all of life. The entire story found in scripture, which pertains to all of life is relevant to understanding this gospel, which is really the heart of it all.
Again, Jesus is the gospel in his person and work for us and for the world. In his Incarnation in God becoming human, one of us. He did mighty works to direct people to the grace and kingdom of God come in him, the King. In his teachings he spoke the very words of God in a way that fulfilled every word of God that preceded him, as the Prophet. And he presented himself once for all as the final sacrifice for all humankind in his death on the cross for the forgiveness of our sins, as the Priest. And by his resurrection we receive new life, resurrection life, even the eternal life in knowing him and the Father who sent him. We enter into this by faith which includes repentance, and by baptism. And thus we are joined not only to Christ, but also to his body the church. And we are called to be witnesses of this good news.
Here is Paul’s summary of the good news:
Now, brothers and sisters, I want to remind you of the gospel I preached to you,which you received and on which you have taken your stand. By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain.
For what I received I passed on to you as of first importance: that Christ died for our sins according to the Scriptures, that he was buried, that he was raised on the third day according to the Scriptures, and that he appeared to Cephas, and then to the Twelve. After that, he appeared to more than five hundred of the brothers and sisters at the same time, most of whom are still living, though some have fallen asleep. Then he appeared to James, then to all the apostles, and last of all he appeared to me also, as to one abnormally born.
For I am the least of the apostles and do not even deserve 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 to me was not without effect. No, I worked harder than all of them—yet not I, but the grace of God that was with me. Whether, then, it is I or they, this is what we preach, and this is what you believed.
But if it is preached that Christ has been raised from the dead, how can some of you say that there is no resurrection of the dead? If there is no resurrection of the dead, then not even Christ has been raised. And if Christ has not been raised, our preaching is useless and so is your faith. More than that, we are then found to be false witnesses about God, for we have testified about God that he raised Christ from the dead. But he did not raise him if in fact the dead are not raised. For if the dead are not raised, then Christ has not been raised either. And if Christ has not been raised, your faith is futile; you are still in your sins. Then those also who have fallen asleep in Christ are lost. If only for this life we have hope in Christ, we are of all people most to be pitied.
But Christ has indeed been raised from the dead, the firstfruits of those who have fallen asleep. For since death came through a man, the resurrection of the dead comes also through a man. For as in Adam all die, so in Christ all will be made alive. But each in turn: Christ, the firstfruits; then, when he comes, those who belong to him. Then the end will come, when he hands over the kingdom to God the Father after he has destroyed all dominion, authority and power. For he must reign until he has put all his enemies under his feet. The last enemy to be destroyed is death. For he “has put everything under his feet.” Now when it says that “everything” has been put under him, it is clear that this does not include God himself, who put everything under Christ. When he has done this, then the Son himself will be made subject to him who put everything under him, so that God may be all in all.
(Note: Many end his summary of the good news after verse 11: “…this is what we preach, and this is what you believed.” I prefer to include through verse 28 which includes the Second Coming and the end of all things.)