The word Injil occurs several times in the Quran (3:4, 3:49, 3:66, 5:47, 5:67, 5:69, 5:111; 7:158; 9:111; 48:30; 57:28) and refers to the revelation to Isa (Jesus). Muslims believe that Injil was the Gospel given to Jesus, may peace be on him. We do not believe that the Injil in the Quran refers to the four Gospels or the New Testament. In Quran, the Injil is instruction for the righteous. According to the Holy Quran:
“And We caused Jesus, son of Mary, to follow in their footsteps, fulfilling that which was revealed before him in the Torah; and We gave him the Injil which contained guidance and light, fulfilling that which was revealed before it in the Torah, and a guidance and an admonition for the God-fearing.” (Al Quran 5:47)
What is the present day equivalent of what the Holy Quran describes as Injil? Could it be the Q document? Q is sometimes called the Synoptic Sayings Source. What gave me this idea was a comment by one of the experts in the four hour PBS documentary ‘From Jesus to Christ: the First Christians.’ Elaine Pagels says in the documentary, “Whoever collected the sayings of ‘Q’ wasn’t interested in the death of Jesus, wasn’t interested in the resurrection of Jesus, thought the importance of Jesus was what he said, what he preached.” This description parallels what the Holy Quran has to say about Injil.
According to Encyclopedia Britannica:
“‘Q’ biblical literature in the study of biblical literature, is a hypothetical Greek-language proto-Gospel that might have been in circulation in written form about the time of the composition of the Synoptic Gospels—Mark, Matthew, and Luke—approximately between 65 and ad 95. The name Q, coined by the German theologian and biblical scholar Johannes Weiss, is a reference to the German word Quelle (‘source’).
Most biblical scholars agree that the authors of Matthew and Luke based their written accounts largely on The Gospel According to Mark. Matthew and Luke, however, both share a good deal of material—largely made up of logia (Greek: ‘sayings’) attributed to Jesus—that is absent from Mark. This led biblical scholars to hypothesize the existence of an undetermined source from which the shared material was drawn: Q, sometimes called the ‘lost source.’ While no actual source document has been found and some scholars doubt that Q ever existed, others have attempted to reconstruct it through intensive textual analysis.”
Please read this knol along with the knol about the Gospel of Thomas, as there are several parallels between the two: