Sa’d al-Falaha, the freed slave of ‘Umar, or Ibn Sa’d al-Falaha narrates that ‘Umar ibn al-Khattab (may Allah be pleased with him) said: “The Arabs are not among the People of the Book Christians; the animals they slaughter are not lawful for us, and I will not leave them until they accept Islam or I fight them.”
Hadith Referenceمسند الإمام الشافعي / كتاب الأطعمة والصيد والذبائح / 1533