What gospel did Jesus and the twelve apostles preach?
Jesus and the twelve apostles preached the Gospel of the Kingdom, declaring that the King had come and was ready to set up the Kingdom promised to Israel since Abraham. That message identified Jesus of Nazareth as the Christ, the Messiah of Israel, offered to the nation of Israel.
Les explains that Jesus and the twelve operated under the Gospel of the Kingdom, which was simply that the King is here and ready to set up the Kingdom offered to Israel since Abraham was given the covenant. The whole scope of that Kingdom message was that Jesus of Nazareth is the Christ, the Messiah of Israel. This contrasts with Paul's Gospel of Grace, which reveals that the same Messiah who was crucified, shed His blood, buried, and rose from the dead is the Savior of the whole human race, not just Israel.