Assume that you meet a man on the street who introduces himself as “John” and tells you two facts about himself, and you observe that John has black hair and brown eyes.
Now assume that John continues down the street, meets me and tells me the same two facts about himself as well as a third, and I also observe the color of John’s hair and eyes.
Now, both you and I have met the same John, but I know something you don’t about him, namely the third fact.
This is basically how I think of Islam and Christianity, but with the following twist:
Assume that I see you at a dinner party, and we both realize we met John on the same day. I tell you the third fact which John told me, but you don’t believe me, so your knowledge of John is incomplete. Furthermore, you begin to forget the first fact John told you, so you just make up another fact about him, which isn’t true.
In the above example John is obviously the monotheistic God and Author of all creation, the great “I AM.” Both you and I therefore know and speak of the same God, but we know him differently. Indeed, in human terms, what we know about a person makes all the difference in how we relate to that person. All the more with God, who is our Heavenly Father.