The baseline definition of an “evangelical” comes from Historian David Bebbington’s famous “quadrilateral” of evangelical traits: biblicism, crucicentrism, conversionism, and activism. Each point, when carried along by the richest of biblical understanding, provides a reliable (though admittedly abridged) framework for understanding Christianity.

But what happens when those things become poor and nominal? Is a nominal foundation of biblicism, crucicentrism, conversionism, and activism going to be thick enough to survive the current cultural assault?

Statistically, the answer is no. By any measure, as evangelicalism has reduced itself to the thinnest expression of each trait, the retention rate of those raised within the church has precipitously dropped. One thing that must be done to reverse this trend is for evangelical churches to thicken upon each point of Bebbington’s quadrilateral.

Thin biblicism gives lip service to God’s Word. Thick biblicism is unashamed of God’s Word.Thin crucicentrism proclaims that Christ is mighty to justify but not mighty to sanctify. Thick crucicentrism proclaims that Christ saves from sin and to righteousness.Thin conversionism assumes that dramatic crisis conversions are the norm for children raised in the covenant community. A thick doctrine of conversion assumes that covenant children come to saving faith through the divine preparations of the church: catechisms, covenant renewal worship, and praying parents that faithfully nurture their children’s soul.Thin activism defines justice in the way the culture does. Thick activism defines justice as God does.

These are only a few of the things needed to reverse the trend. Thin Christianity is a powerless thing. It is those who have the thickened gospel of Jesus Christ as presented in the Bible who will make the deepest mark on their families, friends, co-workers, and neighborhoods.

D.W. Bebbington, Evangelicalism in Modern Britain: A History from the 1730s to the 1980s (Grand Rapids: Baker, 1992).

Jason Cherry is a teacher and lecturer of literature, American history, and economics at Providence Classical School in Huntsville, Alabama. He graduated from Reformed Theological Seminary with an MA in Religion and is the author of the book The Culture of Conversionism and the History of the Altar Call, now available on Amazon.