Eid al-Adha, the „Feast of Sacrifice” is one of the most important feasts of the Muslim calendar and it falls on the 10th day of Dhu al-Hijjah, the last month of the Islamic lunatic calendar. The Eid honours the willingness of Abraham (Ibrahim) to sacrifice his son Ishmael (Ismail) as an act of obedience to God's (Allah) command. However, before Ibrahim could sacrifice his son, a voice from heaven stopped him and God provided him a lamb to slaughter as a „great sacrifice”. In commemoration of this intervention, animals are sacrificed ritually during the first day of the Feast. The family will eat about a third of the meal a third goes to friends and relatives, and the remaining third is donated to the poor and needy.
Edward William Lane about the Eid al-Adha in Egypt:
On the tenth of “Zu-l-Heggeh” (the last month of the year) commences the Great Festival, “El-’Eed el Kebeer,” which… lasts three days, or four... Every person puts on his best clothes or new suit; but it is more common to put on new clothes on the minor ‘eed [Eid al-Fitr]. Prayers are performed in the mosques on the first day, soon after sunrise, as on the other festival; and the same custom of visiting and congratulation, and giving presents (though generally of smaller sums) to servants and others, are observed by most persons. The sacrifice that is performed on the first day, which is the day of the pilgrim’s sacrifice… It is a duty observed by most person who can easily afford to do it. For several previous days, numerous flocks of sheep, and many buffaloes, are driven into the metropolis, to be sold for sacrifice. Another custom observed on this festival, that of visiting the tombs… On this latter ‘eed, most persons who have the means to do so prepare a dish called “fetteh”, composed of boiled mutton, or other meat (the meat of the victim), cut into small pieces, placed upon broken bread, upon which is poured the broth of the meat, and some vinegar flavored with a little garlic fried in a small quantity of melted butter, and then sprinkled over with a little pepper.
/Lane, Edward William: An Account of the Manners and Customs of the Modern Egyptians, The American University in Cairo Press, 2012., p487./