Your book has the following verses within it:
How can you say, “We [the Jews] are wise, for we have the law of the LORD,” when actually the lying pen of the scribes has handled it falsely?’ … (From the NIV Bible, Jeremiah 8:8)
The Translation that you use shows something that is not implied by the passage when taken in context. The passage relates to forcing Isreal to the correct faith by taking their land from them. Another translation does not say that the pen did anything, but that scribes handled it wrong. In other words, they ignored it or did not teach it. That passage, when taken with all of Jeremiah, refers to those who adapt idolatry instead of Judaism
Deuteronomy 31:25-29
25 he gave this command to the Levites who carried the ark of the covenant of the LORD :
26 “Take this Book of the Law and place it beside the ark of the covenant of the LORD your God. There it will remain as a witness against you.
27 For I know how rebellious and stiff-necked you are. If you have been rebellious against the LORD while I am still alive and with you, how much more will you rebel after I die! 28 Assemble before me all the elders of your tribes and all your officials, so that I can speak these words in their hearing and call heaven and earth to testify against them.
29 For I know that after my death you are sure to become utterly corrupt and to turn from the way I have commanded you. In days to come, disaster will fall upon you because you will do evil in the sight of the LORD and provoke him to anger by what your hands have made.”
Again, that does not imply or even say that anyone will physically change anything in Scriptures. See, we understand that God is truly all-powerful, and he can prevent man from messing up his Word. It seems like Muslims do not think that God can do that.
Do Christians accept the validity of these verses from their Bible?
Muslims do not have a problem accepting the above verses as being true.
If I show you to be a lier, using your own words, why should I beleive anything you say? I should not. If you show that the Bible is corrupt, using the Bible’s own words, why should you accept anything in it?
But, perhaps, you want it both ways. It is corrupt when it shows Islam to be false, Muhammed to be a wolf in sheeps clothing, and Jesus to be God but it is true when you can prove Islam correct by it.
I am sorry, but either the Bible is correct about everything or it is not. If it correct about everything, you are in serious trouble for denying it. If it is incorrect about everything, you are in serious trouble trying to use a lie to prove your point as true.