The gospel is the good news of Jesus Christ for salvation. Why do we need salvation? Because fundamentally, all humans are sinful. In the beginning, God created Adam and Eve sinless and appointed Adam as the covenant representative of all humanity. But Adam sinned and broke the covenant God made with him and so all of humanity was plunged into sin. “All have sinned and fallen short of the glory of God” (Rom. 3:23).
But that’s not the end of the story, because God did not leave us in our sin, but promised to send His Son to defeat sin and death in Himself. This Son is Jesus Christ, who, for us and for our salvation, took on a true human nature, lived a perfect life, died a death in our place, and rose again from the dead. Anyone who trusts in Christ for salvation will be united to Him, receive his Holy Spirit, and have eternal life.