What gospel did Jesus and His disciples preach before the accomplishment?
Before the accomplishment, Jesus and His disciples preached the gospel of the kingdom—the good news that the King is coming, the King is here, and the King was ready to set up His kingdom as offered to Israel. He and the Twelve preached it for almost three years.
Les explains that before the accomplishment there could be no gospel as we know it, because it hadn't been accomplished. What Jesus and the Twelve knew and preached was the gospel of the kingdom: the King is coming, the King is here. It was the good news that the King was ready to set up His kingdom as it was being offered to Israel. Les points out that Jesus used that backdrop—the kingdom gospel He and the 12 had been preaching for almost three years. He also notes that this same gospel of the kingdom will be preached again at a future time in all the world for a witness unto all nations, and then the end shall come.