varian
Abraham is traditionally considered to be the first Jew and to have made a covenant with God. Because Judaism, Christianity, and Islam all recognize Abraham as their first prophet, they are also called the Abrahamic religions.
So the Jews, Christians and Moslems all believe in an omnipotent deity - the same omnipotent deity fostering good, not evil.
So why do they hate each other enough to kill each other?
And why does this omnipotent God allow it to happen?
You are overlooking the fact that a great many people "belong" to a religion only in name.
This applies to members of all religions.
IF we all really tried to keep the Ten Commandments and to love our neighbours as ourselves, there might still be wars and hatred in the world, but I assume there would be a lot less of both.
But love of selv intrudes and causes people to treat others unfairly
As to why an omnipotent God allows this to happen, the answer is simple; He gave us free will and leaves it to us to choose between good and evil and to choose to obey his commandments or not.