In the timeline of Jesus, the first occurrence of the gospel shows up in Luke with an Angel speaking to some shepherds:
Luke 2:10 - 11 (HCSB)
"But the angel said to them, "Don't be afraid, for look, I proclaim to you good news of great joy that will be for all the people: today a Savior, who is Messiah the Lord, was born for you in the city of David."The Greek that gets translated "I proclaim to you good news" here is euangelizomai, which is related to euaggelizó: to announce good news. Euaggelizó gets translated as preaching the gospel in other New Testament verses.
So shouldn't we start with this first occurrence to determine what the gospel is?
The angels are declaring that Jesus has come. That the Messiah, a Savior, the Lord had arrived. This is good news for all people.
But wait, I just found an earlier occurrence of the term for gospel in the New Testament. Gabriel speaking to Zechariah in Luke 1:19 has the term euangelisasthai which also gets translated as gospel elsewhere. Here the good news is about the birth of John the baptist. It was good news, but should we conclude this is the gospel that we are to share with the world as followers of Christ?
Do you see where I am going with this? There are many verses in the Bible that have the term gospel, or good news. 1 Cor 15:1 is one verse that often gets used as a proof text for a certain emphasis on the good news message.
I recognize that there are many good news messages in Scripture. However will you consider exploring with me the good news message that Jesus and His disciples preached?
Yes Jesus did preach the gospel.
And He taught His disciples to do the same.
The first 4 books of our New Testament are known as the gospels, and have a lot to say on the topic. They are a great place to start. What do you think the gospel is according to the gospels?
By the way... I think the Angels did a great job introducing us to the gospel that Jesus came to share.
(And by the way #2: the whole of 1 Cor 15 fits well within the gospel Jesus preached, likely a future post. I don't see it as two different gospel messages.)