From Pope John Paul II's Crossing the Threshold of Hope:
"Whoever knows the Old and New
Testaments, and then reads the Koran, clearly sees the process by which
it completely reduces Divine Revelation. It is impossible not to note
the movement away from what God said about himself, first in the Old
Testament through the Prophets, and then finally in the New Testament
through His Son. In Islam, all the richness of God's self-revelation,
which constitutes the heritage of the Old and New Testaments, has
definitely been set aside. "Some of the most
beautiful names in the human language are given to the God of the
Koran, but He is ultimately a God outside of the world, a God who is
only Majesty, never Emmanuel, God with us. Islam is not a religion of
redemption. There is no room for the Cross and the Resurrection. Jesus
is mentioned, but only as a prophet who prepares for the last prophet,
Muhammad. There is also mention of Mary, His Virgin Mother, but the
tragedy of redemption is completely absent. For this reason not only
the theology but also the anthropology of Islam is very distant from
Christianity."
Me: I think this an excellent summary statement.