But God and Jesus Christ are the same . . .
Then discussion should be had regarding the difference between the Gospel and the ministry of men.
God is the Author of the Gospel message, and Paul is not the sole believer and deliverer of that message.
Jews and Gentiles have been given the good news of the Saviour through Godly promise since the beginning of time, and in the fullness of time, witnessed Him with their own eyes.
All way before Paul ever saw Him.
The mantle of the preaching of the Gospel does not fall upon the shoulders of Paul, but is the commission of the Holy Spirit of Christ. Always has been and always will be.
God Himself, convicts and convinces men of His Truth. John 16:13-15
I'll have to differ with you on all that.
It is crystal clear evident in the Scripture that the content of Paul's preaching of the gospel of Christ is different from that content preached by the Twelve.
They were preaching to Israel that Jesus was their Prophesied Christ.
In contrast, Paul's is an everyman ministry not only after Israel's fall, but one that would not be preaching to a non-Israelite that Jesus was their Prophesied Christ - for He was not.
Both aspects of the gospel of Christ share both similarities, and differences.
In Matthew thru John, for example, what are Israelites expected to believe the gospel of Christ is, those three and a half years prior to the Cross - that He died for their sins?
No.
Rather, that He IS THEIR PROPHESIED Christ.
What is it in Early Acts?
That He Whom THEY had Crucified WAS THEIR PROPHESIED Christ.
Faith is the issue in each case.
At the same time, it's object differs somewhat.
And as does the expectation of required accompanying behaviour in each of those cases.
Rom. 5:8
Acts 17:11,12