The more we desire for that which is superfluous, the more we meet with difficulties; our strength and possessions are spent in unnecessary things, and are wanting when required for that which is necessary.
MaimonidesAn 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.
MaimonidesThe soul is subject to health and disease, just as is the body. The health and disease of both . . . undoubtedly depend upon beliefs and customs, which are peculiar to mankind.
Maimonides