Nothing can be irrelevant to the proposition that Christianity is true

If Christianity should happen to be true ... then defending it may mean talking about anything and everything. Things can be irrelevant to the proposition that Christianity is false, but nothing can be irrelevant to the proposition that Christianity is true. All things not only may have something to do with the Christian God, but must have something to do with Him if He lives and reigns. 
-G. K. Chesterton