I am blind and do not see the things of this world; but when the Light comes from Above, it enlightens my heart and I can see, for the Eye of my heart sees everything. The heart is a sanctuary at the center of which there is a little space, wherein the Great Spirit dwells, and this is the Eye. This is the Eye of the Great Spirit by which He sees all things and through which we see Him. If the heart is not pure, the Great Spirit cannot be seen, and if you should die in this ignorance, your soul cannot return immediately to the Great Spirit, but it must be purified by wandering about in the world. In order to know the center of the heart where the Great Spirit dwells you must be pure and good, and live in the manner that the Great Spirit has taught us. The man who is thus pure contains the Universe in the pocket of his heart.
–Black Elk, from Joseph Epes Brown, The Spiritual Legacy of the American Indian.