The Book of Sacrifices (Kitab Al-Adahi)

Muslim :: Book 22 : Hadith 4835

Anas b. Malik reported: Allah's Messenger (may peace be upon him) addressed us on the day of 'Id al-Adha. He smelt the odour of flesh and he prohibited thern from slaughtering (the animals before the 'Id prayer), saying: He who slaughtered the animals (before the 'Id prayer) should do that again (as it is not valid as a sacrifice).

Source materials are from the University of Southern California MSA site
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