What a Muslim knows through his source of “revelation” is where the road forks. For the revelation received through the false prophet is at odds with the Way, the Truth, and the Life. While Islam mimics true religion in many aspects, it is an obvious counterfeit, inspired by hateful jealous spirits who are insane with the envy of our redemption and salvation.
So in summary, a Muslim does indeed worship the same God as Jews and Christians through natural theology, through the right use of his reason. While what he knows of God via false revelation is indeed false, and stands in contradiction to everything we know to be most true and beautiful about God.
Excellent summary!
I think this was essentially what the Pope was saying and why he was inviting them to consider reason. Interestingly, the Muslims seem to have realized this, and many of them are furious with his speech - they wanted an “apology,” which of course he would not and did not give them, and in fact he repeated much of the essence of the Regensburg lecture.
Where does revelation come from, and how can it be false?