Is this a question that needs to be answered? Isn’t it a bit like asking if the existence of God can be proved? Why do we need to prove it? Why do we need to know if Muslims worship the same God as do we? What difference might that make? Having said this, let me offer a few thoughts on why an answer might have some significance. It has been said that if the subject isn’t the same, the predicates don’t matter. In other words, if we aren’t talking about the same God, then what we have to say about God may be quite different and it won’t matter.
 Anyone who has read Jack Miles’ Biography of God will know that the biblical story portrays God with many different faces. In the First Testament God is creator, warrior, jealous lover, mother, etc. etc. Then came Jesus and as Christians we believe He was God’s Messiah and that God was in Christ and so appears in yet another form, that of a human being, who suffers betrayal, crucifixion, who dies and then is raised back to life.
 In some ways these images of God seem contradictory. How can God who ordered David to kill women, children and cattle, and who accepted as praise the Psalmist’s desire to “dash innocent babies against a rock,” be the same God as the Father of our Lord Jesus Christ? Marcionites said this couldn’t be; the Church finally said it was. What Christians did at their best was to make sure Jesus remained central to their understanding of the First Testament. In other words, when First Testament stories and promises are taught and studied in the Church it needs to be kept in mind always that God in Christ is the norm for our understanding of who God is, was and will always be and how God works to bring wholeness and healing to a broken world.
 Then Muslims came and said there is no god but God, the God of Abraham, Isaac, Jacob, David, Solomon and Jesus. They believe that the God preached by Muhammad and believed by Muslims is this very same God. There is no god but God. “Our God and your God is One,” repeats the Qur’an. Muslims certainly intend to worship no other God than the God worshiped by Jews and Christians. But having said that, Muslims go on to insist we can never know who God is but only what God wills for us to do. There is no self revelation, only a revealing of God ‘s will. Likewise, they do not accept our understanding of Incarnation or the cross. These are major distinctions, no doubt, but does it mean they worship a different God, by which some might infer a ‘false’ God?
 I’ve often pondered the experience of Paul. Before his conversion, he certainly knew well what we might call the will or law of God. He was steeped in Rabbinic training. But on the road to Damascus, he experienced something different. He saw what appeared to be a bright light and it sent him reeling to the ground. In response to a voice from heaven he called out: “Tell me Lord, who you are?” The answer was simple: “I am Jesus whom you are persecuting.” That Jesus of Nazareth, whom the rulers had recently killed and hung upon a tree, should turn out to be the Lord, the Messiah, came as a shock to this Jewish Zealot. In response Paul had to spend considerable time rethinking his theology and his understanding of the way God works to redeem people. It caused a dramatic turn about. But did this new understanding mean that Paul began to worship a different God, or to worship God differently? Certainly his discernment, his comprehension of God was radically altered. He never again wielded a sword in the defense of his new faith experience or set out to persecute and imprison others who thought differently. Yes, he worshiped God differently, but was he worshiping another God? We might argue, as some do, that through his encounter with Christ, Paul moved from a worship that was false to one that is true. In other words, the issue is one of true or false worship. But is worshiping God ‘falsely’ the same as worshiping a false God? I don’t think so.
 Likewise for Muslims. Just because their comprehension of who God is and how God works in history to bring about human wholeness has different contours than our own should not mean they thereby worship a different God. Do they worship God differently? Yes, in some ways they surely do, as do the Jews. Do they worship a different God? Certainly that is not their intention, and if it’s not their intention, why should we intentionally try to make it so?
 Finally, we must leave it to God. As the Arabs say: God knows. A fitting close to such a query may be Jesus’ response to the woman at the well in Samaria: “God is Spirit and those who worship God, [in this case be they Jew, Christian or Muslim,] must worship in spirit and truth.”