Ata' (may Allah have mercy on him) narrates from Sayyiduna Jabir (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) made it obligatory; then he narrated the previous narration and said: "He also fixed something upon the people of food," but I have forgotten it.
This is how Muhammad bin Ishaq bin Yasar narrated it, but the narration of those who report it from Umar (may Allah be pleased with him) is more numerous and better known. And Allah knows best.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الديات / 16176