Ata (may Allah have mercy on him) said: The Christians of the Arabs are not People of the Book; the People of the Book are the Children of Israel, to whom the Torah and the Injil came. As for the people who joined them, they are not of them.
The Shaykh (may Allah have mercy on him) said: Sayyiduna Umar and Sayyiduna Ali (may Allah be pleased with them both) also take the Christians of the Arabs in this same sense, and (hold) that their slaughtered animals are not to be eaten.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13987