Here’s an irony, surely. The Gospel to which everyone turns for their definition of the “gospel” is one of the few books of the New Testament in which the euangelion word-group does not appear. The other gospel-free texts are Titus, James, 2 Peter, the letters of John, and Jude—all minor epistles and three of them Johannine. It’s John who gives us the classic statement, so beloved of “evangelicals”, so often the theme of “evangelists”: “For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life” (Jn. 3:16). But he nowhere uses either the noun euangelion or the verb euangelizō.
Does that tell us anything interesting? I think it does. I think that the anomaly highlights a pervasive and persistent misunderstanding of “gospel” in the New Testament.