For I am not ashamed of the gospel, for it is the power of God for salvation to everyone who believes, to the Jew first and also to the Greek. For in it the righteousness of God is revealed from faith for faith, as it is written, ‘The righteous shall live by faith.’ Romans 1:16,17 (ESV)
The gospel message is that Jesus’ death on the cross paid the debt that we owe for our rebellious sins against God and that we can be forgiven of our sins and restored to fellowship and made right with God if we admit our rebellion against God’s authority in our lives and surrender our lives to the lordship of Jesus.