Took out the quote pertaining to Black Elk's words about the Wounded Knee Massacre, as they are actually Neihardt's words and not Black Elk's. This can be found in "The Sixth Grandfather: Black Elk's Teachings Given to John G. Neihardt" page 55 in the footnote. For more accurate Black Elk quotes, this would be a better resource as it is the unabridged collection of the interviews.
Misattributions to Black Elk from Neihardt's fabrications
Many of the quotes in this article attributed to Black Elk in Black Elk Speaks are actually Neihardt's fabrications. This is evident when comparing the words in Black Elk Speaks to the original transcripts published in The Sixth Grandfather. It is troubling how frequently Neihardt's fabrications are misattributed to Black Elk, even the 2008 edition of Black Elk Speaks acknowledges a large extent as fabrications.
Compare in Black Elk Speaks:
I was still on my bay horse, and once more I felt the riders of the west, the north, the east, the south, behind me in formation, as before, and we were going east. I looked ahead and saw the mountains there with rocks and forests on them, and from the mountains flashed all colors upward to the heavens. Then I was standing on the highest mountain of them all, and round about beneath me was the whole hoop of the world.* And while I stood there I saw more than I can tell and I understood more than I saw; for I was seeing in a sacred manner the shapes of all things in the spirit, and the shape of all shapes as they must live together like one being. And I saw that the sacred hoop of my people was one of many hoops that made one circle, wide as daylight and as starlight, and in the center grew one mighty flowering tree to shelter all the children of one mother and one father. And I saw that it was holy.
To in The Sixth Grandfather, p. 133-134:
[The] western black spirit said: "Behold this day, for this day is yours." [I will have the power to shed many happy days on people, they tell me.] "Take courage, for we shall take you to the center of the earth." They [the spirits] said: "Behold the center of the earth for we are taking you there." As I looked I could see great mountains with rocks and forests on them. I could see all colors of light flashing out of the mountains toward the four quarters. Then they took me on top of a high mountain where I could see all over the earth. Then they told me to take courage for they were taking me to the center of the earth. All the sixteen riders of the four quarters were with me going to the center of the earth and also this man by the name of One Side. We were facing the east and I noticed something queer and found out that it was two men coming from the east and they had wings. On each one's breast was a bright star. The two men came and stood right in front of us and the west black spirit said: "Behold them, for you shall depend upon them." Then as we stood there the daybreak star stood between the two men from the east. There was a little star beside the daybreak star also. They had an herb in their hands and they gave it to me, saying: "Behold this; with this on earth you shall undertake anything and accomplish it." As they presented the herb to me they told me to drop it on earth and when it hit the earth it took root and grew and flowered. You could see a ray oflight coming up from the flower, reaching the heavens, and all the creatures of the universe saw this light. [The] western black spirit said: "Behold all over the universe." As I looked around I could see the country full of sickness and in need of help. This was the future and I was going to cure these people. On the east and north people were rejoicing, and on the south and west they were sick and there was a cloud over them. They said: "Behold them who need help. You shall make them over in the future." After a while I noticed the cloud over the people was a white one and it was probably the white people coming.