What gospel did Peter preach to the masses on the Day of Pentecost?
The Bible tells us that when the people heard the apostle testify, They were pricked in their heart, and said . . . Men and brethren, what shall we do?
Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost” (Acts 2:37-38).
Peter did not tell these people just to “believe and be saved.” Nor did he ask them to merely make a decision, to cast a vote for Jesus.
No, he told them to repent first, and then be baptized in obedience to Christ!
What gospel did Paul preach to the pagan Athenians on Mars Hill?
He told them very directly, “God . . . now commandeth all men everywhere to repent” (Acts 17:30).
These Greek intellectuals had no trouble believing in God. In fact, you could say their very pastime was “believing” in many gods—first this one, then that one.
Whenever someone came along preaching a god persuasively, they believed in it. So, they believed—but they did it while living in sin.
Simple belief was not enough!
Paul told these men, “No! No! Jesus cannot simply be added to your list of gods. You may believe in them all, but you can’t do that with Jesus.
He has come to save you from your sins and He commands all His followers to repent and be cleansed!”
Later, Paul preached the same gospel of repentance to King Agrippa: “I was not disobedient unto the heavenly vision: but shewed first unto them of Damascus, and at Jerusalem, and throughout all the coasts of Judea, and then to the Gentiles, that they should repent and turn to God, and do works meet for repentance” (Acts 26:19-20).
Paul is saying, “Everywhere I’ve been, I’ve preached repentance. And genuine repentance proves itself by its actions!”
These passages make clear to us that the apostolic church preached unabashedly the same gospel John and Jesus preached: "Repent for the remission of your sins!”