As-salaamun Alaikum brother:
While the Holy Qur'an mentioned "of the book", it may refer to the Torah, Psalm and Gospel which was clearly mentioned in some ayats. It is claimed that the bible has, in it, the Torah, Psalm and Gospel but I feel that this is not what the Holy Qur'an is referring to.
Hello... Thanks for your question. I may not be the average person who is on this site, my name is Daniel from the link "Hello from a Monotheist outside of Islam", basically someone who endeavours to be grounded in the same theology of God as you do. Re your question, firstly if we begin with a starting point of the Hawariyuun of Nabi Isa, and end with the Holy Books known in Arabia by the Prophet Muhammad, it makes things a lot lest complicated.
According to history, the Injil that was held to by the followers of Jesus was the Hebrew Gospel, based on the Gospel according to Matthew. Matthew in particular is a problem for the church, because of its positiveness to the “Sharia of the Hebrews” (Torah), as opposed to Paul’s writing of law free for the Greek speaking world. It is highly likely that some sort of copy of the Hebrew Gospel is what Waraqa Bin Naufel was trying to translatefrom Hebrew to Arabic (Al-Bukhari ), with the followers of Isa migrating to Arabia after being expelled from Jerusalem by Roman forces.
However this was not the Injil the Prophet Muhammad was calling for reform in the interpretations of the “People of the Book”, so not to refer to God as 3 persons. (QS 4:171). The people using the Hebrew Matthew in the Mecca region were script monotheists, non-trinitarians and being Semitic, enemies of Rome.The only scriptures of the Torah, Zabur Injil in Arabia was in Syriac. This is what the Qu’ran would have been referring to. That means Prophet Muhammad only could ever read the Torah Zabur Injil in Syriac, which I am not sure was known to him. Despite this, the message of the Torah, Zabur, Injil was often orally communicated in Arabic, which left people prone to deception. We must remember, Qur’an is about bringing reform to the Trinitarian views of those holding the Injil. This gives away the greatest clue immediately. In placing an unbiased History of the church of the East in the background of the Qur’an, the Qur’an becomes alive with a lot more meaning. This is the problem with theories of corruption of scripture that neither classical Islam interpreters or the Qur’an supports.
I should add :
a) I believe Muhammad would have disliked (as I do) the term “Old and New Testament” as it had anti-semitic / replacement connotations (ie. Injil replaced Torah; Rome replaced Jerusalem; East replaced West etc.)
b) The above does not mean endorsement of Trinitarian dogma.
c) Important to remember that a portion of the New Testament are letters written to the Greek speaking world, dealing with the concessus of the hawariyuun for them to not be obligated to circumcision, but following the monotheism of Abraham..
Hope this helps. It is hard to keep short (-:
Wasalam