“The Crust and the Core” is the clever epilogue to this book (pp. 241–44):

Kevin DeYoung. The Good News We Almost Forgot: Rediscovering the Gospel in a 16th Century Catechism. Chicago: Moody, 2010. 252 pp.

Excerpts:

This has been a book about theology, about knowing theology and loving theology. But if we’ve really paid attention to the Heidelberg Catechism, this should also be a book about warmhearted experiential faith. In fact, knowing and loving theological truth is what produces the warmhearted experiential faith.

Sadly, too many Christians are asked to choose between theology and experience, between head and heart, between having convictions and being kind. These are false dichotomies . . . . We ought to be hugging theologians . . . . [W]e need to have a theological core without being theologically crusty. . . .

[E]very Christian must be shaped from the inside out by a set of convictions about who God is and what He has accomplished in Jesus Christ. . . .

So, core, yes. Crust? No. . . .

What makes a Christian crusty? A number of things. For starters, it’s an attitude. It’s a demeanor where being Calvinist or paedobaptist or inerrantist (three things I am gladly) are put on like armor or wielded like weapons, when they are meant to be the warm glow of a Christian whose core radiates with love for Christ and the gospel. I believe in theological distinctives—I believe in them and I believe it is good to have them—but if the distinctives are not manifestly the flower of gospel root, the buds aren’t worth the blooming.

A second mark of crusty Christians is approachability, as in, not having any. There is a sizing up-ness that makes some theological types unnecessarily prickly. They are bright and opinionated and quickly analytical. They can also be incessantly critical. Crusty Christians are hard to be around. They are intimidating instead of engaging and growling instead of gracious. They are too willing to share their opinions on everything and unable to put any doctrine in any category not marked “absolutely essential.”