"A casual stroll through the lunatic asylum shows that faith does not prove anything."
I've always liked Nietzsche's quote about faith. It might seem that this quote undercuts the Christian in her or his faith but perhaps Nietzsche's point holds true and actually gives credence to the Christian faith over against the faith of a lunatic. Even perhaps there is Biblical credence to the quote.
James wrote, "faith by itself, if it is not accompanied by action, is dead" (James 2:17). Therefore it is not our faith that does anything for anyone, it is not our faith that saves, and it is not our faith that proves. It is the work that we do from faith in Jesus that testifies to the truth of the Gospel. It is our action that makes sense of faith and lifts it to the level of truth over insanity. It is what we do with our faith that makes it all worth while and even threatens to prove. Faith proves nothing... "a person is justified by what he does and not by faith alone" (James 2:24). Therefore, may you go and walk by faith and not by sight into the work for which God has created you and saved you.