The knowledge of anything, since all things have causes, is not acquired or complete unless it is known by its causes.
AvicennaThere are no incurable diseases — only the lack of will. There are no worthless herbs — only the lack of knowledge.
AvicennaThe world is divided into men who have wit and no religion and men who have religion and no wit.
AvicennaGod, the supreme being, is neither circumscribed by space, nor touched by time; he cannot be found in a particular direction, and his essence cannot change. The secret conversation is thus entirely spiritual; it is a direct encounter between God and the soul, abstracted from all material constraints.
Avicenna