The Church is not a people united by common ideas, ideas which collectively go under the name “Christianity.” When the Bible speaks of a people united by faith it does not simply mean that we have the same beliefs about reality. Though the New Testament does use “faith” to refer to a set of teachings (e.g., 1 Cor. 16:13; 1 Tim. 4:1; 2 Tim. 4:7), “faith” stretches out to include one’s entire “stance” in life, a stance that encompasses beliefs about the world but also unarticulated or inarticulable attitudes, hopes, and habits of thought, action, or feeling.
-Peter Leithart, Against Christianity, 14.