The Jews worship God, but in a false manner. From the summa on whether there can be anything pernicious in the worship of the true God?
As Augustine states (Cont. Mendac. xiv), “a most pernicious lie is that which is uttered in matters pertaining to Christian religion.” Now it is a lie if one signify outwardly that which is contrary to the truth. But just as a thing is signified by word, so it is by deed: and it is in this signification by deed that the outward worship of religion consists, as shown above (II-II:81:07). Consequently, if anything false is signified by outward worship, this worship will be pernicious.
Now this happens in two ways. On the first place, it happens on the part of the thing signified, through the worship signifying something discordant therefrom: and in this way, at the time of the New Law, the mysteries of Christ being already accomplished, it is pernicious to make use of the ceremonies of the Old Law whereby the mysteries of Christ were foreshadowed as things to come: just as it would be pernicious for anyone to declare that Christ has yet to suffer. On the second place, falsehood in outward worship occurs on the part of the worshiper, and especially in common worship which is offered by ministers impersonating the whole Church. For even as he would be guilty of falsehood who would, in the name of another person, proffer things that are not committed to him, so too does a man incur the guilt of falsehood who, on the part of the Church, gives worship to God contrary to the manner established by the Church or divine authority, and according to ecclesiastical custom. Hence Ambrose [Comment. in 1 ad Cor. 11:27, quoted in the gloss of Peter Lombard] says: “He is unworthy who celebrates the mystery otherwise than Christ delivered it.” For this reason, too, a gloss on Colossians 2:23 says that superstition is “the use of human observances under the name of religion.”
The Muslims profess the God of Abraham, but do not worship the same God. This is what we do have in common. Muslims, who, professing to hold the faith of Abraham, along with us adore the one and merciful God, who on the last day will judge mankind.
Now I am kinda stuck that they don’t worship the same God as Christianity as the psalms do say that all the gods of the Gentiles are devils. Any false religion is false worship of God or worship of demons. I would say that the muslims worship God, but in a false manner.
This is what St. Thomas Aquinas says about Islam
"Mohammed seduced the people by promises of carnal pleasure to which the concupiscence of the flesh urges us. His teaching also contained precepts that were in conformity with his promises, and he gave free rein to carnal pleasure. In all this, as is not unexpected; he was obeyed by carnal men. As for proofs of the truth of his doctrine, he brought forward only such as could be grasped by the natural ability of anyone with a very modest wisdom. Indeed, the truths that he taught he mingled with many fables and with doctrines of the greatest falsity.
“He did not bring forth any signs produced in a supernatural way, which alone fittingly gives witness to divine inspiration; for a visible action that can be only divine reveals an invisibly inspired teacher of truth. On the contrary, Mohammed said that he was sent in the power of his arms – which are signs not lacking even to robbers and tyrants. What is more, no wise men, men trained in things divine and human, believed in him from the beginning. Those who believed in him were brutal men and desert wanderers, utterly ignorant of all divine teaching, through whose numbers Mohammed forced others to become his followers by the violence of his arms. Nor do divine pronouncements on the part of preceding prophets offer him any witness. On the contrary, he perverts almost all the testimony of the Old and the New Testaments by making them into a fabrication of his own, as can be seen by anyone who examines his law. It was, therefore, a shrewd decision on his part to forbid his followers to read the Old and New Testaments, lest these books convict him of falsity. It is thus clear that those who place faith in his words believe foolishly.”
Summa Contra Gentiles, Book 1, Chapter 16, Art. 4, Footnote 1
Please feel free to disagree with me as this topic does intrigue me.