Religion: A Dialogue, from the Essays of Arthur Schopenhauer
Demopheles: However that may be, I wanted to remind you that you should look at religion more from the practical than from the theoretical side. Personified metaphysics may be the enemy of religion, but all the same personified morality will be its friend. Perhaps the metaphysical element in all religions is false; but the moral element in all is true. This might perhaps be presumed from the fact that they all disagree in their metaphysics, but are in accord as regards morality.
Philalethes: Which is an illustration of the rule of logic that false premises may give a true conclusion.
For me, this creates a strong basis for Zen metaphysics as an approach to religious/spiritual morality, while leaving the mystery of evil, morality and good unexplained.