Ubaydullah bin Abdullah narrates from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that he said: O assembly of Muslims! How can you ask the People of the Book about anything when your Book, which Allah revealed to His Messenger, is the most recent of reports about Allah? You recite it pure, with no adulteration in it. And Allah has told you that the People of the Book altered what Allah had written, changed it, wrote the books with their own hands and said: 'This is from Allah, in order to purchase with it a small price.' [Surah al-Baqarah: 79] Does not the knowledge that has come to you forbid you from questioning them? By Allah! We have never seen any man among them asking you about what has been revealed to you.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20613