What then does the word translated “gospel” mean? The question might seem to be unnecessary (were it not apparently ignored in so many sermons and religious books); everyone knows that “gospel” means “good news.” But if “gospel” means “good news,” then many common notions about the gospel disappear at once. “Good news” is never in the imperative mood; a “gospel cannot possibly consist in directions as to a way of life or in a complex of worthy ideals. If a man comes running in and says in a tone of great eagerness, “I have news for you: Keep the commandments of God; love God and your neighbor.” Such exhortations are indeed exceedingly important and valuable, but they are certainly not news. News consists always, not in exhortations or commands, but in information of facts; a “gospel” is always in the indicative mood. – J. Gresham Machen
Taken from Machen: Selected Shorter Writing edited by D.G. Hart, page 127.