The charge that the Prophet plagiarized the Bible is unfounded due to the following reasons:First, there are hundreds of references in the Qur’an relating to the incidents that occurred deep in the past that are not found in the Bible. For example, Adam’s repentance in Paradise and God’s acceptance of it, which essentially refutes the core Christian concept of original sin. The Qur’an also mentions various incidents of Prophets not found in the Bible, such as Abraham’s being thrown into a fire only to be saved by God and Abraham’s construction of the holy place of worship, the Kaaba, at Mecca. It also recounts many crucial parts of the histories of Noah and Jesus, some of which completely contradict the Biblical account. Where did Muhammad get all of this information? For sure, it could not have been the Bible. How can anyone argue with his right mind that he plagiarized the Bible?
As for the charge that he learned the whole Qur’an from the Christian monk Bahira, this would be an absurd accusation on two counts, at least. First, the meeting between the Prophet and the monk was only for a brief moment in time and when the Prophet was only 12 years old. The monk invited the caravan in which the Prophet was travelling in for a dinner while the caravan was en route to Syria. It would be inconceivable for the Prophet to have learned all of what he needed to learn from Bahira in one short meeting. Moreover, there is no historical record of his learning the Bible from Bahira, although there are records of the monk’s predicting the prophethood of Muhammad that he learned from Jewish –Christian scriptures
Second, vast portions of the Qur’an (including many of its longer chapters, such as Chapters 5, 8, 9, 24, 33, 48, etc.) deal with the political and social issues the Prophet faced in Medina for over ten years. How could these chapters be dictated to him by Bahira? It is mind boggling that such an argument was forwarded by a French author who claimed the Prophet learned the whole of the Qur’an from Bahira in one short sitting.
As mentioned, there are many claims that the Prophet learned a lot of the historical references of the Qur’an from Christians or Jews who lived during his time. One such argument states that there were two Christian missionaries who would visit Mecca during the annual fairs, from whom the Prophet may have received knowledge. However, these Christians had passed away long before the Prophet Muhammad was alive and so it would be impossible for them to have taught him.