Euangelion in Greek, which is translated as “good news” or “gospel,” combines angelos, the word for one announcing news, and the prefix eu-, which means “joyful.” Gospel means “news that brings joy.” This word had currency when Mark used it, but it wasn’t religious currency. It meant history-making, life-shaping news, as opposed to just daily news. [Keller goes on to talk about the “gospel of Caesar Augustus”] …
A gospel is an announcement of something that has happened in history, something that’s been done for you that changes your status forever.