Isn't the Bible corrupted?
No. Manuscripts from centuries before Muhammad match our Bible, and the Quran itself told Christians to judge by the Gospel they had.
The question is when the corruption happened. Before Muhammad? Then the Quran was wrong to call the Gospel guidance and light and to tell Christians to judge by it. After Muhammad? We have complete Bibles copied 250 years before he was born, and they say the same thing ours do.
Copying mistakes exist, and textual scholars catalogue them openly. None of them touches the death and resurrection of Jesus or his claims about himself.
47Let the People of the Gospel judge by that which Allah hath revealed therein. Whoso judgeth not by that which Allah hath revealed: such are evil-livers.
Quran 5:47 (Pickthall) · context
94And if thou (Muhammad) art in doubt concerning that which We reveal unto thee, then question those who read the Scripture (that was) before thee. Verily the Truth from thy Lord hath come unto thee. So be not thou of the waverers.
Quran 10:94 (Pickthall) · context
115Perfected is the Word of thy Lord in truth and justice. There is naught that can change His words. He is the Hearer, the Knower.
Quran 6:115 (Pickthall) · context