“We cannot worthily conceive the grandeur of those sublime and divine promises, if we can conceive them at all; to imagine them worthily, we must imagine them unimaginable, ineffable and incomprehensible, and completely different from those of our miserable experience. ‘Eye cannot see,’ says St. Paul, ‘neither can it have entered into the heart of man, the happiness which God hath prepared for them that love him.'”–Michel de Montaigne
Certainty is the mother of all Blasphemy. It erodes all reason, and casts wisdom into to the depths of hell itself.
Doubt is not the enemy of the faithful, but rather the fuel to the fire that drives their quest for understanding. God, if he is God at all, is beyond us.