The decisive issue between Islam and Christianity is, quite simply, the gospel—the Bible’s account of what God has done, is doing, and will yet do through his Son to redeem his creation. It is this “good news” story of the Creator’s eternal, Son-centered plan of redemption that reveals to us who our Creator truly is. This gospel story is the watershed issue that exposes the dramatic difference between Islam and Christianity. It is not until this difference is grasped that the question of what Christianity and Islam may or may not hold in common can even be addressed.

http://www.christianitytoday.com/ct/2016/july-web-only/christianity-vs-islam-about-cross.html