they all taught the gospel the apostles never parted from the gospel those four books we have in the Bible were written by them and those appointed like Luke and mark.
the apostles role is this here when they each received the spirit and thier calling as one of the twelve appointed witnesses this was going to be thier role in the church
“I have yet many things to say unto you, but ye cannot bear them now.
Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come.
He shall glorify me: for he shall receive of mine, and shall shew it unto you.”
John 16:12-14
the apostles weren’t creating doctrine in the epistles the epistles are companions to the gospel the gospel Jesus preached is the doctrine , but there was a lot of explaining of thkngs he left out because they weren’t grasping a lot of it yet they had no revelation
so if we look at what Jesus began to teach , and the epistles we are they are companions the epistles help us better grasp the gospel because some of it is very parabolic , and somewhat hidden when Jesus spoke it , Peter and Paul and Johns role was to share the revelation given to them when they each received the holt spirit and revelation of the prophets and apostles witness of the gospel
the apostles are all
Preaching the gospel it’s firther more opened understanding so more can grasp it without knowing the prophets they offer revelation of the prophets like this summary of the old and foretelling of the new it’s the apostles doctrine also just a quick summary
“And he said unto them, These are the words which I spake unto you, while I was yet with you, that all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the psalms, concerning me. Then opened he their understanding, that they might understand the scriptures, And said unto them, Thus it is written, and thus it behoved Christ to suffer, and to rise from the dead the third day: And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem. And ye are witnesses of these things.”
Luke 24:44-
revelationtells us that Christ was the promised messiah the law and prophets witnesses would come and now the gospel is preached in Christs name to all
People by the apostles and all the early church when Paul scattered them by persecution it spread the gospel
“As for Saul, he made havock of the church, entering into every house, and haling men and women committed them to prison. Therefore they that were scattered abroad went every where preaching the word.”
Acts 8:3-4 KJV
the word is the gospel that Jesus preached when he was on earth the epistles are all companion writings to help us grasp the gospel and it’s applicable faith To our daily lives so we can walk in the things of salvetion
There’s no conflict between the apostles doctrine and the gospel it’s a matter of revelation so it appears somewhat different it’s better understood in some points