In order to acquire spiritual knowledge, receive inspiration, prepare one's heart for inner revelation, one must try to make one's mentality pliable like water rather than like a rock; for the further along the path of life's mystery a person will journey, the more subtle he will have to become in order to perceive and to express the mystery of life. God is a mystery, His knowledge is a mystery, life is a mystery, human nature is a mystery; in short, the depth of all knowledge is a mystery, even science or art.