[Guruman]

the core of all religion (and judaism and christianity in particular) is faith.

Faith is the belief in something in the abscence of evidence. In order to have faith, one must put aside his reason and choose to believe something that he has know way of knowing one way or the other. People often do this because others tell them of their own faith in these things. Ex: A man's parents believed that when you die your concious soul wallows forever in ketchup until you can write out pi in its entirety. In his childhood he attends a church that supports these beliefs and he is indoctrinated. He then spends most of his waking life trying to get a head start on longwriting pi.

There is of course, no evidence that this will be his fate should he die. He just believes it because he was told to.

If I found out for sure that God not only exists, but is the God of Judaism - I guess I'd be dead already. This is because to know for sure, one needs evidence - and the evidence can only come after death when one supposedly meets his maker.

Therefore the question is moot (with the unlikely exception of God existing and showing himself to you before death.)