Of the ninety plus verses which contain the word "Gospel," at least seventy-five use the definite article "the" with the term. The only time the indefinite article "a" is used, in the form of "another Gospel," is when Paul was rebuking those who insisted there is another Gospel (2 Cor. 11:4; Gal. 1:6)! His actual words are:
"I marvel that ye are so soon removed from him that called you into the grace of Christ unto another Gospel: which is not another; but there be some that trouble you, and would pervert the Gospel of Christ. But though we, or an angel from heaven, preach any other Gospel unto you than that which we have preached unto you, let him be accursed. As we said before, so say I now again, If any man preach any other Gospel unto you than that ye have received, let him be accursed" (Gal. 1:6-9).
There is but one Gospel; it is the Gospel which God's Word tells us; it is the Gospel which has the power to save the lost! Paul wrote: "For I am not ashamed of the Gospel of Christ: for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek" (Rom. 1:16). Notice there is not a Gospel for the Jews, and a Gospel for the Gentiles! While Peter was the Apostle to the Jews, and Paul was the Apostle to the Gentiles (Gal. 2:8), they preached the same message! The Gospel Paul preached, was the same Gospel Peter, James, John, etc., preached; it contained three important parts: "For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the Scriptures; and that He was buried, and that He rose again the third day according to the Scriptures" (1 Cor. 15:3-4).
If you believe the Lord Jesus died for you, call upon Him to save you!