Paul and John the Baptist taught two distinct gospels, both given by God: the gospel of the kingdom and the gospel of the grace of God. Paul’s good news included Christ’s blood payment for our sins and righteousness without the law.
John the Baptist taught the good news of a coming Messiah to establish the long promised kingdom to Israel. Anyone with sin could not enter the kingdom. He water baptized for the remission of sins and for the priesthood (Mark 1:3-4).
Jesus, during his earthly ministry, taught the same message as John (Mark 1:14-15). Yet, he added belief in himself as the Messiah. Anyone who did not believe Jesus was the Son of God was unacceptable with God (John 6:40). The disciples of John may not have identified the Messiah. Followers of the Jesus were required to.
Transition to Peter’s Message
When Jesus died his followers scattered. When Peter resumed the Lord’s ministry he taught Jesus’ message plus the Messiah’s necessary death and resurrection according to the prophets (Acts 2:31-38 and 3:18). All new followers had to believe Peter’s message of water baptism, Messiahship, and resurrection. Denying the resurrection was unacceptable.
Added to Peter’s message was supernatural empowerment with the Holy Ghost. This also was not optional. Every follower of Peter’s message received the promise and power of the Holy Ghost (Mark 16:17, Acts 2:38, 1 John 2:21).
The gospel message was altered or added to three times in the course of only a few years. Followers of John coexisted with followers of Peter and did not understand the resurrection, Messiah, or Holy Ghost (Acts 19:2-3). They were acceptable under John’s ministry and unacceptable under Peter’s. They were not in the upper room. They needed to handle the gospel transition. They needed to get up to speed.
Those Left Behind in Transition
When God reveals new information there are always those under an old message that remain and die. They may never be included in the new message. When they were given God’s message they believed it and acted accordingly. The just shall live by faith.
When you learn to respect the difference between Peter and Paul’s gospels you will ask the same question everyone asks. What happened to the followers of Peter’s gospel if Paul’s was different?
Answer: The same thing that happened to followers of John the Baptist. They lived and died by faith in what God told them. Their message was old and was being replaced by the gospel of the grace of God. Peter’s message was no longer what God was using. Paul updated Peter and Peter backed off. Transition was not unprecedented.