An ignorant man believes that the whole universe only exists for him: as if nothing else required any consideration. If, therefore, anything happens to him contrary to his expectation, he at once concludes that the whole universe is evil. If, however, he would take into consideration the whole universe, form an idea of it, and comprehend what a small portion he is of the Universe, he will find the truth. There are many ... passages in the books of the prophets expressing the same idea.
MaimonidesEvery man should view himself as equally balanced: half good and half evil. Likewise, he should see the entire world as half good and half evil.... With a single good deed he will tip the scales for himself, and for the entire world, to the side of good.
MaimonidesFurther, there are things of which the mind understands one part, but remains ignorant of the other; and when man is able to comprehend certain things, it does not follow that he must be able to comprehend everything.
Maimonides