Paul did not teach anything different than what Jesus taught about the Kingdom of GOD. There is ONLY ONE Saving Gospel.
The Gospel of GOD encompasses the Gospel of the Kingdom of GOD which is
the Gospel of Grace which is the Gospel of of Christ.
Mark 1:14-15 Jesus Preaches in Galilee
Now after John had been taken into custody, Jesus came into Galilee, preaching the gospel of God, 15 and saying, “The time is fulfilled, and the kingdom of God is at hand; repent and believe in the gospel.”
Luke 4:43 Jesus said, “I must preach the Gospel of the Kingdom of God…because that is why I was sent.”
Luke 9:1-2 Jesus called the Twelve together…and sent them out to preach the Kingdom of God.
Acts 1:3 Jesus appeared to them over a period of 40 days and spoke to them about the Kingdom of God.
Acts 8:12 “When they believed Philip as he preached the Gospel of the Kingdom of God and the name of Jesus Christ, they were being baptized, both men and women.”
Acts 20:25 [Paul went about] preaching the Kingdom.
Acts 28:31 Paul “boldly and without hindrance preached the Kingdom of God and taught about the lord Jesus Christ.” (PAUL TEACHING the Gospel of the Kingdom of GOD)
Matt. 24:14 “This Gospel of the Kingdom will be preached in the whole world as a testimony to all nations, and then the end will come.”
Galatians 3:8 And the scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed.
After Jesus’ resurrection Jesus still spoke about the coming Kingdom of GOD for a further 40 days. Acts 1:3
Paul taught the Gospel of the Coming Kingdom of GOD. THE GOSPEL of GOD encompasses the grace of GOD through which ALL Nations shall be blessed
Jesus died and being raised from the dead is ONLY Part of the Gospel. Jesus said I must preach the coming Kingdom of GOD for this is the reason I was sent. Luke 4:43.
In 30 combined chapters in Matthew, Mark and Luke; Jesus spoke nothing of his death and Resurrection. Throughout these 30 chapters Jesus and his disciples were preaching the Gospel of the Kingdom of God.