The gospel existed as far back as the beginning in the old testament, in Genesis when God promised Adam and Eve that the seed of the woman would smash the head of the serpent.

And to Abraham, that through him would come a Blessing to the entire world.

And to Moses when God instructed him to tell the Israelites that another Prophet like him would God raise for them and they should listen to Him

And to David, when God promised him that he would raise him an heir who would sit on his throne forever

And to Mary, when angel Gabriel visited her and announced to her that she would bear the Son of God.

Until John identified Him in the river Jordan and announced Him to the world as the Lamb of God who would take away the sin of the world as promised by God in Genesis.

The Kingdom of God is come. Repent, believe in the gospel and be saved�