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"Say (O Muhammad sal-Allaahu 'alayhe wa sallam): "I find not in that which has been inspired to me anything forbidden to be eaten by one who wishes to eat it, unless it be Maytatah (a dead animal) or blood poured forth (by slaughtering or the like), or the flesh of swine (pork, etc.) for that surely is impure, or impious (unlawful) meat (of an animal) which is slaughtered as a sacrifice for others than Allaah (or has been slaughtered for idols, etc., or on which Allaah's Name has not been mentioned while slaughtering), But whosoever is forced by necessity without wilful disobedience, nor transgressing due limits, (for him) certainly, your Lord is Oft-Forgiving, Most Merciful."" [Al-An'aam (6):145]

Narrated 'Abdur Rahman bin Abi Bakra's father:

Once the Prophet was riding his camel and a man was holding its rein. The Prophet asked, "What is the day today?" We kept quiet, thinking that he might give that day another name. He said, "Isn't it the day of Nahr (slaughtering of the animals of sacrifice)" We replied, "Yes." He further asked, "Which month is this?" We again kept quiet, thinking that he might give it another name. Then he said, "Isn't it the month of Dhul-Hijja?" We replied, "Yes." He said, "Verily! Your blood, property and honor are sacred to one another (i.e. Muslims) like the sanctity of this day of yours, in this month of yours and in this city of yours. It is incumbent upon those who are present to inform those who are absent because those who are absent might comprehend (what I have said) better than the present audience." [The Book of Knowledge Volume 1, Book 3, Hadeeth 67]