And [mention, O Muhammad], when Allah took a covenant from those who were given the Scripture, [saying], "You must make it clear to the people and not conceal it." But they threw it away behind their backs and exchanged it for a small price. And wretched is that which they purchased.
Quran 3: 187
So woe to those who write the "scripture" with their own hands, then say, "This is from Allah ," in order to exchange it for a small price. Woe to them for what their hands have written and woe to them for what they earn.
Quran 2: 79
Ibn `Abbas said, "O Muslims? How do you ask the people of the Scriptures, though your Book (i.e. the Qur'an) which was revealed to His Prophet is the most recent information from Allah and you recite it, the Book that has not been distorted? Allah has revealed to you that
the people of the scriptures have changed with their own hands
what was revealed to them and they have said (as regards their changed Scriptures): This is from Allah, in order to get some worldly benefit thereby." Ibn `Abbas added: "Isn't the knowledge revealed to you sufficient to prevent you from asking them? By Allah I have never seen any one of them asking (Muslims) about what has been revealed to you."
Saheeh Bukhary
Vol. 3, Book 48, Hadith 850