There is a lot, of course, that could and needs to be said about defining “the gospel.” But here’s one important thing to say: you can’t understand the biblical gospel apart from the biblical storyline.
Don Carson puts it well in his essay, “The Biblical Gospel” (in For Such a Time as This: Perspectives on Evangelicalism, Past, Present and Future, ed. Steve Brady and Harold Rowdon [London: Evangelical Alliance, 1996], pp. 75-85). The following excerpt is from pp. 80-81, line breaks mine:
God is the sovereign, transcendent and personal God who has made the universe, including us, his image-bearers.
Our misery lies in our rebellion, our alienation from God, which, despite his forbearance, attracts his implacable wrath.
But God, precisely because love is of the very essence of his character, takes the initiative and prepared for the coming of his own Son by raising up a people who, by covenantal stipulations, temple worship, systems of sacrifice and of priesthood, by kings and by prophets, are taught something of what God is planning and what he expects. In the fullness of time his Son comes and takes on human nature. He comes not, in the first instance, to judge but to save: he dies the death of his people, rises from the grave and, in returning to his heavenly Father, bequeaths the Holy Spirit as the down payment and guarantee of the ultimate gift he has secured for them—an eternity of bliss in the presence of God himself, in a new heaven and a new earth, the home of righteousness.
The only alternative is to be shut out from the presence of this God forever, in the torments of hell.
What men and women must do, before it is too late, is repent and trust Christ; the alternative is to disobey the gospel (Romans 10:16; 2 Thessalonians 1:8; 1 Peter 4:17).
This story-line, and its connection with the gospel, could be fleshed out in a number of ways. But the point is simply this: the good news of salvation through Jesus Christ makes sense in the context of this story-line and in no other.
If, instead of this world-view, this storyline, some other is adopted, the good news of Jesus Christ no longer makes sense or is so badly distorted it is no longer the same thing.
For instance, if one adopts a pantheistic world-view, then ‘sin’ takes on an entirely different configuration and there is no transcendent God to whom to be reconciled. In that case, the ‘good news’ cannot be the announcement of God’s reconciling act in the death and resurrection of his Son, by which he bore his people’s penalty.
If one adopts some naturalistic world-view, something similar could be said.
If one holds that history is going nowhere or in circles determined by impersonal fate, then the notion of final judgement and ultimate division between bliss and the abyss is incoherent—and so too the good news that Christ reconciles rebels to their Maker, prepares them for glory, enabling them even now to enjoy foretastes of the kingdom still to be consummated.
