When a vision comes from the thunder beings of the West, it comes with terror like a thunder storm; but when the storm of vision has passed, the world is greener and happier; for wherever the truth of vision comes upon the world, it is like a rain. The world, you see, is happier after the terror of the storm. … you have noticed that truth comes into this world with two faces. One is sad with suffering, and the other laughs; but it is the same face, laughing or weeping. … as lightning illuminates the dark, for it is the power of lightning that heyokas have.

Black Elk Speaks (1961)