Revelation

Both Christians and Muslims believe God has given a special revelation to humanity, but they disagree over the nature of this revelation. Muslims believe God revealed his will to various prophets in the past, including to the Hebrew prophets and to Jesus, but that the Old and New Testaments of the Christian Bible have been corrupted and thus are not authoritative. The Qur’an is the definitive and final revelation. Muhammad didn’t author the Qur’an; he was the passive recipient of dictated revelations.  

Christians, by contrast, hold that God has revealed himself in the Old and New Testaments of the Christian Bible which is a record of encounters with God by peoples, in their times and places, through which God reveals not only his will but ultimately Himself in the Messiah Jesus.

For a scholarly discussion see; The Word of God: Revelation in Christianity and Islam

by Miroslov Volf