In March, 2008, Graeme Goldsworthy delivered a lecture at Southern Baptist Theological seminary titled “Biblical Theology and its Pastoral Application.”
In it he gave one of the clearest statements of why the Reformation was needed and what the problem was in the way the Roman Catholic church had conceived of the gospel.
Both Catholicism and allegorical interpretation of Scripture involved the dehistoricizing of the Gospel. The Reformation rehistoricized both the Gospel and the Old Testament.
The prime focus recovered in the Reformation was the justification of the sinner on the basis of the objective, historic work of Christ for us.
Catholicism had reversed the vision so that the prime focus was on the work of Christ or his Spirit within us.
This meant the reversal of the relationship of sanctification to justification. Infused grace, beginning with baptismal regeneration, internalized the Gospel and made sanctification the basis of justification. This is an upside down Gospel.
I would add that this “upside down” gospel has not gone away—neither from Catholicism nor from Protestants who equate our faithfulness (sanctification) with faith (understood as a receiving of Christ’s faithfulness as the sole ground of God being 100% for us).
When the ground of justification moves from Christ outside of us to the work of Christ inside of us, the gospel (and the human soul) is imperiled. It is an upside down gospel.