Eid al-Adha or Feast of Sacrifice is the most important feast of the Muslim calendar. It concludes the Pilgrimmage to Mecca. Eid al-Adha lasts for three days and commemorates Ibraham's (Abraham) willingness to obey God by sacrificing his son. Muslims believe the son to be Ishmael rather than Isaac as told in the Old Testament. Ishmael is considered the forefather of the Arabs. According to the Koran, Ibrahim was about to sacrifice his son when a voice from heaven stopped him and allowed him to sacrifice a ram instead.
The feast re-enacts Ibrahim's obedience by sacrificing a cow or ram. The family eats about a third of the meal and donates the rest to the poor.