I have argued in a couple of posts recently (see below) that the “gospel” in the New Testament is not the personal message that Jesus died for your sins but the public proclamation, in the particular historical setting of the crisis of first century Israel, that God has raised his unjustly executed Son from the dead and has given him authority to judge and rule, first over Israel, then over the nations. But John Shakespeare asks about 1 Corinthians 15:1-5:
Now I would remind you, brothers, of the gospel I preached to you, which you received, in which you stand, and by which you are being saved, if you hold fast to the word I preached to you—unless you believed in vain. For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, that he was buried, that he was raised on the third day in accordance with the Scriptures, and that he appeared to Cephas, then to the twelve. (1 Cor. 15:1–5)
For the sake of completeness and in hope of putting the topic to bed for a while, here is how a I think this needs to be understood.