The Day of Atonement is the only fast provided in the Law; it is only on this occasion that (a) the Jews are required to " afflict their souls," (b) the High Priest enters the Holy of Holies, (c) the High Priest offers incense before the mercy seat and sprinkles it with blood, and (d) the scapegoat or Azazel is sent away into the wilderness, bearing upon him all the iniquities of the people.