Gospel means "good news." Your debt has been paid, the death penalty has been paid, you are free.
Here's the Gospel of Jesus Christ: 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 Corinthians 15:1-4 - The apostle Paul tells us what the gospel is: "Moreover, brethren, I declare to you the gospel which I preached to you, which also you received and in which you stand, by which also you are saved, if you hold fast that word which I preached to you—unless you believed in vain. For I delivered to you first of all that which I also received: 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.
Jesus brought in a little child as a living object lesson to show who enters the kingdom of heaven.
Matthew 18:3 - Jesus said: "Unless you become like this little child you will not enter the kingdom of heaven." This is how to be saved, it is simply child like, as simple as A - B - C.