(ANSAmed) - ROME - Id al-Idha (the feast of the sacrifice) or Id al-Kabir (Great Festival) begins tomorrow for Muslims, one of the most important holidays of the year. For the occasion, numerous animals are sacrificed (usually the ram), the meat of which is distributed among the faithful. The holiday falls on the 10th day of the Muslim month based on the lunar cycle, denominated Dhu l-hijja (literally 'that of the pilgrimage'). The pilgrimage (hajj) follows a ritual definitively fixed by the Prophet Mohammed just before his death in 632 AD and is one of the 5 pillars of Islam. The Feast of the Sacrifice is the commemoration of the sacrifice of Ismail, son of the patriarch Abraham and Hagar. The Koran (Sura 37) tells that Ismail was to be sacrificed as Allah wished, when a voice of an angel stopped the hand of Abraham and the boy was substituted with a ram. According to the Jewish Bible, it was Isaac, son of Abraham and Sara, to escape the sacrifice, which took place on Mt. Moriah as told in Genesis (chapter 22). The date of the feast is calculated every year on the basis of the lunar cycle, but in order to unify the dates for the entire Muslim world. As for the general panorama, Libya stands apart with a government decision which bumped the feast forward to today. (ANSAmed).