The genuine gospel: Content
The risen Christ clarified the true gospel that was to be preached to all nations
Luke 24:44-47 And he [Jesus] 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. 45 Then opened he their understanding, that they might understand the scriptures, 46 And said unto them, Thus it is written, and thus it behoved Christ to suffer, and to rise from the dead the third day: 47 And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem.
Peter preached the true gospel to Cornelius and company in Acts 10 this way:
Acts 10:39-4339 And we are witnesses of all things which Jesus did both in the land of the Jews, and in Jerusalem; whom they slew and hanged on a tree: 40 Him God raised up the third day, and shewed him openly; 41 Not to all the people, but unto witnesses chosen before of God, even to us, who did eat and drink with him after he rose from the dead. 42 And he commanded us to preach unto the people, and to testify that it is he which was ordained of God to be the Judge of quick and dead. 43 To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins. (See also Acts 2:22-37)
Paul summarizes the content of the true gospel in I Corinthians 15 this way: I Corinthians 15:1-4 Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have. received, and wherein ye stand; 2. By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. 3. For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; 4. And that he was buried, and that he rose again the third day according to the scriptures:
Paul and Philip preached the gospel of the kingdom by preaching Christ:
Acts 28:23: " So when they had appointed him a day, many came to him at his lodging, to whom he explained and solemnly testified of the kingdom of God, persuading them concerning Jesus from both the Law of Moses and the Prophets, from morning till evening."
Acts 8:5 Then Philip went down to the city of Samaria, and preached Christ unto them.
Acts 8:35 Then Philip opened his mouth, and began at the same scripture, and preached unto him (Eunuch) Jesus.