The God of the scriptures revealed Himself over and over to the jews.. they have refused Him ..the god they "pray to "is not a triune God..remember ..that is why they cried to crucify Christ, when He told them He was God.. , No the god of the jews has no power to save
https://carm.org/do-christians-muslims-jews-worship-same-god
I for one have a serious problem with Judaism's view of God, based largely on this:
For as the Father raiseth up the dead, and quickeneth them; even so the Son quickeneth whom he will. For the Father judgeth no man, but hath committed all judgment unto the Son: That all men should honour the Son, even as they honour the Father. He that honoureth not the Son honoureth not the Father which hath sent him.
(John 5:21-23)
They have indeed rejected the God of Abraham, Isaac, and Jacob, if they have rejected God's Messiah. Jesus' statement above makes it impossible to miss this.
But the problem extends beyond that. Do a thought experiment with me. Just for fun. :) What if someone said they believed in the God of Abraham, Isaac, and Jacob, but they have these magic glasses and these mysteriously inscribed gold plates, and have come to the conclusion that this God is actually a highly evolved form of Adam? Would you still agree that they worship the God of Abraham, Isaac, and Jacob? Or have they kept the name only, and displaced the reality?
And then it gets even trickier, because none of us has a perfect idea of God. So at what point, what threshold would be sufficiently off-base to say, nope, we are no longer talking about the same Being. Buddhists believe in a version of God too. But that God is really just a label for everything, i.e., pantheism. But I have known Christians who didn't realize God knew what they were thinking. That's defective too, but much less so. So the question of degree enters into the analysis.
Don't misunderstand me here. I'm not saying I have a pat answer to the question. I do think one has to be careful to look at the content behind the label, and not just accept a label because it has been claimed. On the Judaism question, I would say they are indeed dishonoring the true God, but I probably could not have reached that conclusion without that passage from Jesus to confirm it, because they do have a version of God that is close enough to Christian truth it would be hard to say He is some totally alien deity.
But Islam does not present that problem. Their deity is not a personal God. Kismet, fate, the impersonal, unknowable, remote god, more like the eternally distant Gnostic divinity at the end of infinite emanations. It isn't just the absence of the Trinity that is the problem. They worship a being that is truly alien to the person revealed in the Hebrew and Christian Scriptures. It is more purely pasting a false label on their deity, which emerged from their idolatry, their worship of the black rock (an old meteor) in Mecca by bowing down to it from every point on the planet. That IS their god, the one they worship with their bodies, and it has nothing in common with the God of Abraham, Isaac, and Jacob, other than their claim of a label. To say they and we worship the same God is to completely ignore reality. It is not even a close question.
Peace,
SR