Good grief...it’s Matthew Mark Luke and John. You might want to read them!! Lots of jesus’s own words in that.
Those are BOOKS we call the gospels ..they contain the gospel along with many of the events and encounters of Christ..
They tell us that Jesus PREACHED the gospel
Mat 4:23 And Jesus went about all Galilee, teaching in their synagogues, and preaching the gospel of the kingdom, and healing all manner of sickness and all manner of disease among the people.
Mat 11:5 The blind receive their sight, and the lame walk, the lepers are cleansed, and the deaf hear, the dead are raised up, and the poor have the gospel preached to them.
When the epistles were written the gospels had not been written , yet the epistles refer to the gospel .. the gospel is a specific message of Christ that was taught by the writers of the epistles . I thought that maybe as a student of the bible you might know what it is