The topic of the sources of the Quran – which is strongly related to contemporary theology – is something that orientalists frequently research about in their Islamic and Quranic studies, due to its extreme importance and sensitivity. In their studies they have come up with results that are opposite to what the Muslims believe, as they claim that the holy Quran has sources other than Divine revelation, although they have different views in defining it. This paper aims at studying this topic through reviewing their views and arguments, and then scientifically critiquing them appropriately, proving the falsity of their claims in this field. This study is important due to them proving the non-revelation source of the Quran and its origin not being divine, ultimately meaning that it has no validity and cannot be used to prove the prophecy of the Prophet of Islam (s.a.w.), leading to dismissing Islam itself. The opposite for this is also correct, in that proving its divinity proves Islam and everything else.