The first time the gospel was ever preached was to an audience of 3: Adam, Eve, and the Prince of Darkness.
In the beginning we see God’s awesome goodness and the first glimpse of his mercy. In the very same breath that he speaks judgment against the serpent he speaks hope to Adam and Eve and all of creation, when he promises to destroy the deceiver.
Protoevangelium is the term used for this first time the gospel is mentioned in the Bible, which occurs in Gen. 3:15.
God makes a prophecy that Christ will overcome the devil and redeem mankind. The ruin that Adam and Eve created through rebellion would be made right by God himself.
Now the message was a bit cryptic and shrouded in mystery, but war had been declared, an army had been assembled and at the helm stood the “Captain of our Salvation," Jesus Christ our Lord.
Thousands of years later our Salvation came. At the cross Satan’s power was broken, sin's chains undone, death overcome, and love shown in a way that no one had ever seen before.
Our salvation is secure, and it can never be undone. Those who believe do not need to fear the devil or man, for they cannot take away what Christ has done for them (Heb. 13:6). It won’t be long until Christ returns with his sword of righteousness to bring this battle to its final end. There will be no prisoners of war. There will only be those who will see death and those who will see life. This life is found in the gospel and was promised at the beginning of creation. This promise was not only made to Adam and Eve, it was made to all who believe.