Question: So what is the Gospel?
Answer: The Gospel is the death, burial and resurrection of Jesus Christ (1st Corinthians 15:1-11), in whom there is life by believing in His name. (John 20:31)
1st Corinthians 15:1-11: “Now I make known to you, brethren, the gospel which I preached to you, which also you received, in which also you stand, by which also you are saved, if you hold fast the word which 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 according to the Scriptures, and that He was buried, and that He was raised on the third day according to the Scriptures, and that He appeared to Cephas, then to the twelve. After that He appeared to more than five hundred brethren at one time, most of whom remain until now, but some have fallen asleep; then He appeared to James, then to all the apostles; and last of all, as to one untimely born, He appeared to me also. For I am the least of the apostles, and not fit to be called an apostle, because I persecuted the church of God. But by the grace of God I am what I am, and His grace toward me did not prove vain; but I labored even more than all of them, yet not I, but the grace of God with me. Whether then it was I or they, so we preach and so you believed.”
Galatians 1:6-9: “I am amazed that you are so quickly deserting Him who called you by the grace of Christ, for a different gospel; which is really not another; only there are some who are disturbing you and want to distort the gospel of Christ. But even if we, or an angel from heaven, should preach to you a gospel contrary to what we have preached to you, he is to be accursed! As we have said before, so I say again now, if any man is preaching to you a gospel contrary to what you received, he is to be accursed!”
The “different gospel” referred to at Galatians 1:6-9 was a Gospel which denied the grace of Christ, and embraced salvation by obedience to the Law. Given that what Paul preached was the death, burial and resurrection of the Lord Jesus Christ, and labeled as “the Gospel,” and, by way of comparison, given what John Calvin taught, which was Theistic Fatalism, and labeled as “the Gospel,” surely the possibility exists, therefore, that Paul and Calvin had two distinctly different concepts of what the Gospel was.