It is wrong and dishonest to quote anything or any book out of context, whether it be the Bible or the Qur'an. No Muslim should resort to such an approach. God wants us to spread the truth by honest means only. Having said that, it should also be said that Muslims, Christians and Jews do not believe in every single thing that the Bible says. No reasonable person can do that.
I Samuel chapter 17, verses 23 & 50 says that David killed Goliath. II Samuel 21:19 says that Elhanan killed Goliath. I Chronicles 20:5 says that Elhanan killed not Goliath but the brother of Goliath whose name is given as Lahmi. Obviously, no reasonable person should believe all three reports.
Knowing this, the editors of the King James Bible decided to fix this problem by making a slight correction to the Bible. They inserted three words in II Samuel 21:19 to make it say there also that Elhanan killed the brother of Goliath. You will notice that the three words the brother of appear there in italics to distinguish them from the rest of the Bible.
The Interpreter's One Volume Commentary on the Bible calls this a "conflict of tradition about Goliath" (p.179; see also p. 212). It says further that the author of Chronicles changed the story where it said that Elhanan killed Goliath to make it say that Elhanan killed Lahmi the brother of Goliath. The same commentary says further that the statement in I Chronicles is "incorrect" (p. 180). So here we have a Bible commentary written by Christians, published by Christians, and sold in Christian bookstores - yet it openly disagrees with a statement in the Bible. This was done not because Christians wanted to disbelieve in the Bible, but because they had to choose, among different statements in the Bible, which statement is more believable.
Now, this approach to the Bible does not mean that Christians cannot refer to the Bible or quote from it or write commentaries on it. Likewise for Muslims. Although Muslims, like their Christian and Jewish neighbors, do not believe in every single thing the Bible says, students of comparative religion should be allowed to study both the Qur'an and the Bible. Every honest student, however, will pay close attention to the context of what he or she reads, and apply scrupulous exactitude when quoting from either book.
May God help us and guide us all to understand His true message regardless in which book that truth is contained.