@adrian009 is more knowledgeable to answer this.
In my view, The Text itself tells us, all Scriptures are inspired by God.
A claim, somewhat similar to the Quran. Here we have a Person, called Jesus who claims to be sent by God. The same is claimed by Quran, that Muhammad is sent by God.
The difference is, Quran makes it appear in many instances that God is revealing the stories of past to Muhammad.
In Gospels, For example Luke 1, we have an author who does not introduce himself. But tells us, he investigated everything, and is narrating an orderly accounts of what happened at the time of Jesus ministry.
Is, the author of Luke, whoever he is, telling us truth? Are the stories he is telling regarding life of Jesus, His encounters, sayings, and stories of apostles true?
It depends on us to believe it or not. But I dont see if it can be proved.
Likewise, the Quran, claims to tell stories of the past prophets and people.
Are they true stories? It depends on us if we believe it or not. But I dont see how it can be proved.
My personal perception tells me, these books were all work of divine.