After some research I found that Muslims often cite The Gospel of Barnabas (GOB) in defense of Islamic teaching. In fact, you can easily find copies to purchase in most Muslim countries. The document supports the central Islamic teaching, and popular Muslim belief, that Jesus did not die on the cross, but rather, Judas Iscariot died in His place—substituted at the last moment. (Not the Truth). The Gospel of Barnabas goes against the Bible.
The Gospel of Barnabas is a fraud and the evidence is overwhelming. It first appeared, written in Italian, around 1500 AD. No father or teacher in the Christian church ever quoted from it.
Another reason Muslims quote from GOB is because it contains the statement supposedly made by Jesus, "I am not the Messiah . . . I am indeed sent to the house of Israel as a prophet of salvation; but after me shall come the Messiah." But this even contradicts the Qur'an's claim that Jesus WAS the Messiah, that He would die, that He would rise from the dead, that He would perform miracles and that the Roman soldiers and the Jews believed that it was Jesus that they crucified (Sura 3:55; cf. 19:33)! Go figure.
The substitution theory, that someone else died on the cross in Jesus' place, has been circulated since 150 AD, probably due to the influence of Gnosticism. Joseph, Judas, and Simon the Cyrene who carried the cross for Jesus have all, at one time or another, been linked to this ridiculous theory. Since the death and resurrection of Jesus are crucial to the Christian faith, it's no surprise Satan tries to discredit or change the facts. But there is not a shred of first-century testimony by friend or foe of Christianity regarding "switching" places with Jesus on the cross. If for no other reason, it's totally implausible because it would demand total ignorance on the part of those closest to Jesus, His disciples, and the Romans.
When the Bible was put together those who did this work had a high standard. Not just anything and anyone who said they had the truth but they had to follow a prescribed pattern. These were set up as Councils.
The councils followed something similar to the following principles to determine whether a New Testament book was truly inspired by the Holy Spirit: 1) Was the author an apostle or have a close connection with an apostle? 2) Is the book being accepted by the body of Christ at large? 3) Did the book contain consistency of doctrine and orthodox teaching? 4) Did the book bear evidence of high moral and spiritual values that would reflect a work of the Holy Spirit?
As a reminder, it is crucial to remember that the church did not determine the standard. No early church council decided on the standard. It was God, and God alone, who determined which books belonged in the Bible. It was simply a matter of God’s imparting to His followers what He had already decided. The human process of collecting the books of the Bible was flawed, but God, in His sovereignty, and despite our ignorance and stubbornness, brought the early church to the recognition of the books He had inspired.