What is a crusty christian?
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.”
—Kevin DeYoung, “The Crust and the Core,” in The Good News We Almost Forgot (Moody, 2010),