There is neither a historical evidence nor a hint in the Quran that Jesus wrote down a book:
- No such book is ever menitoned in historical religios documents. It is not even related that Jesus has ever written down anything (except once in the sand).
- Suppose Jesus had written down something, why should those who fervently believed in him and even gave their lives for their faith have failed to relate it? Why should authors of the written Gospel not at least integrate it into their accounts?
The main underlying misunderstanding is that the Gospel writings are the Gospel. The right term to use for the written texts is to speak of "Gospel accounts".
The Term Gospel, Greek: Euangelion, therefrom Arabic: Injil, means "Good Message". The Gospel is the Message God gave to the people through Jesus (p.b.u.h). This message was given by teachings and example deeds. Both, teachings and deeds are reported in the Gospel accounts, which were written down by scholars (John as an eye-witness, Mark in frist link in chain, as an author who had access to direct witnesses, Luke as a second link, Matthew and Thomas without known authors). They must be understood as hadith.
There are few more writings that may contain some truth but are too late to be reliable (e.g. the Infancy Gospel falsely attributed to James which shows some contents confirmed in the Quran), and a lot of earlier or later forgeries that intend to propagate teachings of the author as teachings of Jesus. The so-called Gospel of Barnabas is quite evidently a medieval forgery and - although the intention behind its writing is to adapt the accounts to Islamic teachings - it has no value.
The fact that the Injil is cited as a singular in the Quran may have two reasons:
- As mentioned above, the Euangelion is actually the message of God, which is not divided.
- The Syriac christian Tatian had made a compilation of the four canonical gospels in Aramaic in a single account which was still widely used in the Aramaic communities.
This whole time the Injeel was just memorized inside Isa's mind. If the Injeel was actually a written text, don't you think someone would have found it by now? Instead, people keep finding very old un-canonical gospels written by Isa's disciples. No one ever finds the actual Injeel or what some people call "The Gospel of Jesus".
I could be wrong but I think the Injeel was in Isa's mind this whole time....not in actual text.
I fully agree to this understanding. Any assumption of a "lost" Gospel written by Jesus (p.b.u.h) lacks any evidence, so that the "evidence" read from the Quran is just a misinterpretation.