Luke Chapter 9
9:1 Then he called his twelve disciples together, and gave them power and authority over all devils, and to cure diseases.
9:2 And he sent them to preach the kingdom of God, and to heal the sick.
9:3 And he said unto them, Take nothing for your journey, neither staves, nor scrip, neither bread, neither money; neither have two coats apiece.
9:4 And whatsoever house ye enter into, there abide, and thence depart.
9:5 And whosoever will not receive you, when ye go out of that city, shake off the very dust from your feet for a testimony against them.
9:6 And they departed, and went through the towns, preaching the gospel, and healing every where.
The above verses are just one of many stating that the disciples of Jesus went forth and preached the gospel. This gospel was not the books of the bible we have today because they were written at least 35 years after the death of Jesus, going on biblical and Christian accounts, from Wikipedia:-
A gospel (from Old English, gōd spell "good news") is a writing that describes the life of Jesus. The word is primarily used to refer to the four canonical gospels: the Gospel of Matthew, Gospel of Mark, Gospel of Luke and Gospel of John, probably written between AD 65 and 110. They appear to have been originally untitled; they were quoted anonymously in the first half of the second century (i.e. 100–150) but the names by which they are currently known appear suddenly around the year 180. The term "Gospel" refers also to the message itself of the four Gospels or of the whole New Testament.
What the verses are referring to is the message Jesus was giving to his people, the Divine Revelation. Later authors turned parts of this revelation into a “once upon a time, there was a man called Jesus” account which also had some historical facts, but also myths and absurdities; the present day New Testament!
The Revelation give to Jesus is called the Injeel in Arabic and some ‘scholars’ equate this with the Bible, but the Injeel was a ‘book’ given to Jesus and not what we have now.
5:110 Then God will say, “O Jesus, son of Mary! Recall My blessings upon you and your mother. I strengthened you with Sacred Revelation, enabled you to speak eloquently to the people in childhood, and also at the advanced age. I gave you Revelation and wisdom including the Torah and the Gospel. Recall that you told them that you would raise them from dust up into the heights of glory by My leave. You made people see the Truth otherwise given to blind following, by My leave. You healed the wounds of inequity on people by My leave, and you gave a new meaning to life to those who were otherwise no better than dead, by My leave). Recall, how I prevented the Children of Israel from harming you when you came to them with all evidence of the Truth. And those who were bent upon denying the Truth said, “This is nothing but clear deception.” [3:45-48, 3:111, 4:157, 6:123. 7:176]
5:111 Recall, I told the disciples in the Gospel, “Believe in Me and in My Messenger. They said, "We believe, and be Witness that we have submitted."
In the above verse, 5:110, it refers to ‘al-kitaba’ (translated revelation by Dr Shabbir) which also means a book, which all Messengers had from Allah. We can also see that Gospel has been used for Injeel, but this causes confusion as we may think that the New Testament is this Injeel, when it clearly is not.