:salam2:
I am trying hard not to reply these days, but couldn't resist replying to this one.
Three issues raised:
1. What does the Quran say about bible:
Nothing, Quran does the speak about the bible, rather it speaks about the scripture that is in possession of Jews and Christian. As a matter of fact, the bible does not speak about itself either. The word 'bible' is not to be found in the bible itself.
The Quran says 'Jews and Christians have access to truth i.e. authentic scripture and the forgeries in their possession.
Indeed, those who exchange the covenant of Allah and their [own] oaths for a small price will have no share in the Hereafter, and Allah will not speak to them or look at them on the Day of Resurrection, nor will He purify them; and they will have a painful punishment. (3:77)
The Qur'an’s basically makes three accusations.
What Quran criticizes is the way Jews and Christians use their scriptures. It says they have in their scriptures the truth, but they mishandle it. It makes basically three accusations.
(I) The Quran says some of the Jews and Christians pass over much of what is in their scriptures.
So for their breaking of the covenant We cursed them and made their hearts hard. They distort words from their [proper] usages and have forgotten a portion of that of which they were reminded. And you will still observe deceit among them, except a few of them. But pardon them and overlook [their misdeeds]. Indeed, Allah loves the doers of good. (5:13)
O People of the Scripture, there has come to you Our Messenger making clear to you much of what you used to conceal of the Scripture and overlooking much. There has come to you from Allah a light and a clear Book. (5:18)
Example:
Bible texts are produced to show that Jesus used the terms "son of man", "son of God", "Messiah", and "saviour". But each of these terms is applied to other individuals in the Bible. Ezekiel was addressed as "son of man" (Ezekiel chapter 3). Jesus himself speaks of the peacemakers as "sons of God" (Matthew 5:9). Cyrus the Persian is called "messiah" at Isaiah 45:1.
Again these terms are quoted to assert the divinity of Jesus, but the same terms are passed over when referred to other people.
(II) Some of them have changed the words, i.e. they mistranslate it, or misrepresent it, or they add to the meaning of it. They put a different slant on it.
So for their breaking of the covenant We cursed them and made their hearts hard. They distort words from their [proper] usages and have forgotten a portion of that of which they were reminded. And you will still observe deceit among them, except a few of them. But pardon them and overlook [their misdeeds]. Indeed, Allah loves the doers of good. (5:13)
Example:
Christians choose to cite the forty-third chapter of Isaiah as proof that there is only one saviour. Again, translators have tried to obscure the fact that God is the only saviour in the same ultimate sense that He is our only nourisher and protector, though men also have these assigned tasks. By over specifying this pronouncement in Isaiah they hope to have us believe that God equals saviour and Jesus equals saviour therefore Jesus equals God. The conspiracy of modern translation is easily demonstrated. The King James Bible of 1611 is everywhere available. Compare it to a more recent translation, say the New English Translation. In the earlier version we find 2 Kings 13:5 contains the word "saviour", but in the newer version the synonymous word "deliverer" has been substituted. In fact, "saviours", the plural, will be found at Obadiah 21 and Nehemiah 9:27. Here again, by substituting a different word, the connotation of divinity tied to the word "saviour" has been guarded in modern versions by less than honest translation.
(III) And the third accusation is that some people falsely attribute to God what is really written by men.
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. (2:79)
And indeed, there is among them a party who alter the Scripture with their tongues so you may think it is from the Scripture, but it is not from the Scripture. And they say, "This is from Allah ," but it is not from Allah . And they speak untruth about Allah while they know. (3:78)
Interestingly the accusation is in the bible itself.
How do ye say, We are wise, and the law of the LORD is with us? Lo, certainly in vain made he it; the pen of the scribes is in vain. (Jeremiah Chapter 8: 8 KJV)
http://www.sacred-texts.com/bib/kjv/jer008.htm#008
How can you say, ‘We are wise, and the law of the LORD is with us’, when, in fact, the false pen of the scribes has made it into a lie? (Jeremiah Chapter 8: 8 RSV)
http://bible.oremus.org/?passage=Jeremiah+8
Example;
In one of the New Testament Books, Paul goes on to list the men he once baptimised and finished as saying, there were others, but I don’t remember them now. This is the kind of objections Muslims have with some Christians who insist that every word in the bible is the word of God. Is this how God works, that He says don’t expect me to remember it now, it was a long time back? Plus there is other kind of stuff in the bible which we need not to go into right now.
2. Should Muslim quote the bible:
Invite (all) to the Way of thy Lord with wisdom and beautiful preaching; and argue with them in ways that are best and most gracious: for thy Lord knoweth best, who have strayed from His Path, and who receive guidance. (6:125)
Say: "O People of the Book! come to common terms as between us and you: that we worship none but Allah. that we associate no partners with him; that we erect not, from among ourselves, Lords and patrons other than Allah." If then they turn back, say ye: "Bear witness that we (at least) are Muslims (bowing to Allah.s Will). (3:64)
How do we come to common terms between them and us, if we don't know what their scripture says? secondly we need to remember Prophet Muhammad s.a.w didnt knew how to read or write, so he could not have himself used their scripture.
Rather the Quran does that job, of course it does not go by chapter number and verse no, but it mention things which are in their scriptures. For example, one Ayah says that the last Prophet (pbuh) is mentioned in their own scripture.
Those who follow the Messenger (Muhammad), the unlettered Prophet whom they find written in the Torah and the Gospel with them, he enjoins upon them that which is virtuous and forbids them that which is evil; he allows them all that is good and forbids for them all that is foul. And he releases them from their burdens and from the shackles that were upon them. So it is those who believe in him, honour him, assist him and follow the light which has been sent down with him, it is they who will be successful. (7:157)
Other example can we shown but it should suffice.
And Allah swt knows best
3. Debate issue:
I guess we have already discussed that before.
those were mashallah very very beautiful answer 
