You have lots of metaphysical rationalizations and Thomistic references in your arguments…but honestly…I can’t see where you have shown that muslims worship the same God of the Christians. The muslims do not recognize the Trinitarian God…the true God. They reject God the Son and God the Holy Spirit. Therefore, they are not worshipping the true God.
Do you have any Scriptural and patristic sources to support your belief that muslims worship the Trinitarian God…despite the fact that they admit they do not worship the Trinitarian God?
It seems your argument is basically one cannot acknowdege God without acknowledging the three Divine Persons.
According to Scripture, God can be known without access to revelation (Rom. 1:20). This is why St. Paul could say the Greek altar could be dedicated to the same God he was preaching (Acts 17:23), despite the fact that they were not Christians (and therefore did not acknowledge the Trinity).
But no one can reason out the Trinity–it is a mystery of faith that must be revealed (Luke 10:21-22). For example, the truth Christ is the Son of God had to be revealed to St. Peter for him to acknowledge it (Matt. 16:16).
Therefore, if one can acknowledge God from looking at the natural world, but cannot acknowledge the Divine Persons without revelation, then one must be able to acknowledge God without acknowdging the three Persons.
I don’t know much Patristic writing on Islam in particular, other than that of St. John of Damascus, but he seems to support my argument. He says they were idolators until a certain period (they worshipped Aphrodite and the morning star), then Mohammed came around and they became heretics. Now he considers them “mutilators” of God. So they went from committing idolatry (giving divine honor to something other than God) to mutilating God. Mutilation does not change a things essence; one would not say those who adore Zeus or Tlaloc or, in this case, Aphrodite, mutlilates God. To mutlilate God you have to be talking about God. Therefore, it seems according to St. John, Muslim doctrine obscures things about God, it doesn’t offer a different God like their pre-Muhammed religion did.
Here’s his text:
orthodoxinfo.com/general/stjohn_islam.aspx