Ibn Abbas was one of the greatest companions of the Prophet. He held much authority as a Quranic interpreter, for the Prophet prayed to God to make Ibn Abbas a great commentator on the Qur’an and scholar of Islam in general…
Narated by Ibn ‘Abbas :
Once the Prophet embraced me and said, “O Allah! Bestow on him the knowledge of the Book (Qur’an).”
(Saheeh Bukhari Volume 001, Book 003, Hadith Number 075.)
Ibn Abbas said, “How can you ask the people of the Scriptures about their Books while you have Allah’s Book (the Qur’an) which is the most recent of the Books revealed by Allah, and you read it in its pure undistorted form?“
(Saheeh Bukhari, Volume 9, Book 93, Number 613)
Narrated ‘Ubaidullah bin ‘Abdullah:
Abdullah bin ‘Abbaas said, “O the group of Muslims! How can you ask the people of the Scriptures about anything while your Book which Allah has revealed to your Prophet contains the most recent news from Allah and is pure and not distorted? Allah has told you that the people of the Scriptures have changed some of Allah’s Books and distorted it and wrote something with their own hands and said, ‘This is from Allah, so as to have a minor gain for it. Won’t the knowledge that has come to you stop you from asking them? No, by Allah, we have never seen a man from them asking you about that (the Book Al-Qur’an ) which has been revealed to you.
(Saheeh Bukhari, Volume 9, Book 93, Number 614)
Ibn Hazm described the above narrations as:
The soundest Isnad (chain of transmission) or ascription to Ibn Abbas, which is exactly our view. There is no difference between the companions on this matter.
(Ibn Hazm, Al-Fasl fi’l Milal, Volume 2, p. 3)
So we see that Ibn Hazm reinforces the fact that Ibn Abbas truly held this position and that even the companions of the Prophet held the same position as well. Thus there was a consensus amongst the companions that the Christians and the Jews had textually corrupted their scriptures.