Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated: The Jews disputed with the Prophet (peace and blessings be upon him) and said: "Do you eat what we have killed, and not eat what Allah has killed?" So Allah, the Mighty and Majestic, revealed this verse: "And do not eat of that over which the name of Allah has not been mentioned" [Surah al-An'am: 121].
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12243