What is the Gospel?
What is the gospel? Well, the word gospel means "good news." Good news about what? The good news that God so loved the world He gave His only Son, and whoever believes in Him will not perish, but have eternal life. The good news that whoever calls upon the name of the Lord shall be saved.
The good news that Jesus died for our sins and was raised from the dead. The good news that by God's grace we are saved through faith in Christ. The good news that God is reconciling all things to Himself. The good news that Jesus bore our sins on the cross that we might die to sin and live to righteousness. The good news that Jesus reigns forever.
Now, if that doesn't sound like good news, that's because you don't understand the bad news. You have sinned against a holy God and He will destroy you in His righteous judgment. But God shows His love for us in that while we were sinners, Christ died for us. By faith in Jesus, you are forgiven. You're no longer the object of God's wrath but the object of His mercy. And that's good news.
The gospel is not doing nice things for people, but a believer will show the love of Jesus. The gospel is not miraculous healings, but a believer who was dead in their sins has been raised to life in Christ. The gospel is not worldly prosperity, but a believer will inherit the heavenly kingdom of God.
The gospel is a message. Therefore, it must be spoken. Only those who believe the gospel, who repent of their sin and follow Jesus, will be saved from the judgment of God. But how will they know unless they are told? You must believe the gospel, then go and share the good news, when we understand the text.