Sacred Books and Traditions of the Yezidiz, by Isya Joseph, , at sacred-texts.com
The third essential element in the religion of the devil-worshippers is the belief that their sect has taken its origin from Yezid, whom frequently they call God and regard as their ancestral father, to whom they trace their descent. No other worship is offered him. He is given, however, a place of honor in the court of the temple, where, on one side, there is the inscription "Melek Yezid, the mercy of God be upon him"; on the other side "Šeiḫ Adî, the mercy of God be upon him." In the corner of this court a lamp is kept burning all night in honor of the two.