[Romans 16:25 KJV] "Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began,".........Paul is saying his gospel was according to the revelation of the mystery. A mystery is wisdom hid in God and not made known anywhere in scripture until revealed.
[Ephesians 6:19 KJV] "And for me, that utterance may be given unto me, that I may open my mouth boldly, to make known the mystery of the gospel,"........Here again Paul says his gospel was a mystery.
[Ephesians 3:5 KJV] "Which in other ages was not made known unto the sons of men, as it is now revealed unto his holy apostles and prophets by the Spirit;"...........Paul is saying that the mystery was not made known anywhere before it was now revealed to him. Scripture says Paul's gospel is a mystery, so it couldn't have been preached by Peter and the disciples, or in fact, anywhere in scripture. Paul's gospel was faith only in the death and resurrection of Christ for eternal life, without works, without covenants, without the law, without having to be saved through Israel.
[Ephesians 6:19 KJV] "And for me, that utterance may be given unto me, that I may open my mouth boldly, to make known the mystery of the gospel,"........Here again Paul says his gospel was a mystery.
[Ephesians 3:5 KJV] "Which in other ages was not made known unto the sons of men, as it is now revealed unto his holy apostles and prophets by the Spirit;"...........Paul is saying that the mystery was not made known anywhere before it was now revealed to him. Scripture says Paul's gospel is a mystery, so it couldn't have been preached by Peter and the disciples, or in fact, anywhere in scripture. Paul's gospel was faith only in the death and resurrection of Christ for eternal life, without works, without covenants, without the law, without having to be saved through Israel.