Did the Apostle Paul receive further revelation from the Lord that had never been taught before? Who was Paul's message to? The Gentile world?
Paul's message given to him directly by the Lord revealed the doctrine of eternal salvation in its entirety and how to live the crucified life as a new creature living in the Church Age.
What Paul teaches is the same Gospel just different crowd. Paul often spoke to both Jew and Gentile in the same crowd. Paul would speak about Jewish Old Testament history and prophecy to the Jews while he would debate Greek philosophers on their many unknown Gods.
Acts 13:16 New International Version (NIV)
16 Standing up, Paul motioned with his hand and said: “Fellow Israelites and you Gentiles who worship God, listen to me!
All we know in scripture is what Paul had on the road to Damascus. I dont seem to remember a new doctrine that Jesus spoke to Paul about. He simply was told to bring the good news to the Gentiles.
Acts 13:46-47 New International Version (NIV)
46 Then Paul and Barnabas answered them boldly: “We had to speak the word of God to you first. Since you reject it and do not consider yourselves worthy of eternal life, we now turn to the Gentiles. 47 For this is what the Lord has commanded us:
“‘I have made you a light for the Gentiles,
that you may bring salvation to the ends of the earth.’
So what new doctrine? Bring salvation? Same salvation to the Jew as to the Gentiles.
Paul, Peter, James, Author of Hebrews, Jude, and John had more to record to help their readers to be encouraged, to defend against false teachings, and to constantly remind their readers of the one true Gospel taught to them at first. But none of their letters contradict the cross and resurrection.
You will have to show me where it says Paul received a new doctrine. Gentile salvation was prophetic so it technically wasn't a surprise or new either regardless if some of the Apostles was hesitant. Isaiah 65:1 for example
Isaiah 65:1 New International Version (NIV)
65 “I revealed myself to those who did not ask for me;
I was found by those who did not seek me.
To a nation that did not call on my name,
I said, ‘Here am I, here am I.’
Technically it was Peter who recieved the first vision reminding him that Jesus's died for the sins of the World not just jew. Peter was a eyewitness to the Spirit filling Gentiles.
Acts 11:18 New International Version (NIV)
18 When they heard this, they had no further objections and praised God, saying, “So then, even to Gentiles God has granted repentance that leads to life.”