“but continually proclaimed to those in Damascus first, and in Jerusalem, and then all the region of Judea, and even to the Gentiles, that they are to repent and turn to God, performing deeds consistent with repentance.” Acts 26:20 NASB2020https://bible.com/bible/2692/act.26.20.NASB2020

Paul’s gospel was repent and perform deeds consistent with repentance. What is the modern gospel? Ask Jesus into your heart, whatever that means, believe in Him and He will forgive you of all your sins against God then you can spend eternity in heaven with Him. Repentance and asking Jesus into your heart are similar like saying I’m sorry and asking forgiveness are similar. I’m sorry takes less responsibility for our actions and requires nothing of the other person. Asking forgiveness requires humility of us and acceptance by others. Most people never ask forgiveness. Repentance is asking forgiveness of God. It is acknowledging a failure to live God’s way and do God’s will. It is also means a commitment to stop doing those things that God condemns and start doing those things God commands rather than living a self-serving life. Repentance is turning around from the wrong direction and start going in the right direction. This leads to performing deeds in keeping with repentance. What are those? At minimum they are giving generously to the work of God just as God gave His Son to be the Savior of the world. It means serving the mission of the Church which is the winning of the world to Jesus and teaching them to obey everything Jesus commanded just as Jesus did not come to be served but to serve. It also means sharing the gospel with everyone we know in obedience to make disciples as His witnesses so that God’s will for everyone to be saved comes to fruition. If we have never really repented and are not diligent to give, serve and share, maybe we still haven’t ‘believed the gospel,’ maybe we haven’t truly become Christians yet.