The question now arises: What is the content of our ultimate concern? What does concern us unconditionally? The answer, obviously, cannot be a special object, not even God, for the first criterion of theology must remain formal and general. If more is to be said about the nature of our ultimate concern, it must be derived from an analysis of the concept ultimate concern. Our ultimate concern is that which determines our being or not-being. Only those statements are theological which deal with their object in so far as it can become a matter of being or not-being for us.

Systematic Theology (1951–63)