Have you ever noticed that many religious believers -- when faced with something other than unquestioning belief -- will tell you that you "don't understand" what they are saying? They act as if they are making a claim as obvious as DVODVOQVESVNTQVATTVOR. They will not accept a skeptic's judgement of "not established," let alone an outright disbelief. Critical thinking is something they shun.
Well, here's news for such people. Disagreeing with you does not imply a lack of understanding. Neither does agreeing with you mean someone does understand. If you trot this saying out as soon as someone questions you, your belief is not rational. It is not based on anything observable. It doesn't matter if you later turn out to be right. Hey, it could happen. Jesus could come down out of the clouds tomorrow. My wager, however, would be that he won't. I understand what you are saying. But I am not buying what you are selling.