Muslims believe the Quran is the word of God as dictated to Muhammad over a period of two decades. The word was delivered by the angel Gabriel.
One of the tenets of the Islamic religion is acknowledging that the Quran is the word of God. This is an important distinction for Muslims in separating the person who wrote the words of the Quran from the true author. This belief is not dissimilar from the belief that Christians hold about the Bible. According to Islamic tradition, Muhammad believed those things dictated by God and communicated by Gabriel were the final chapter to the Christian texts rather than in competition with them.