That was all part of mohammed's story. He was looking into the various religions of the day and he resented the story of Isaac being chosen over Ishmael. He is the one that started the story, trying to give validity to his satanic verses!
Ishmael’s descendants are the Arab nations.
Genesis 17:20
And as for Ishmael, I have heard you: I will surely bless him; I will make him fruitful and will greatly increase his numbers. He will be the father of twelve rulers, and I will make him into a great nation.
Genesis 16:11-12
The angel of the LORD also said to her: “You are now with child and you will have a son. You shall name him Ishmael, for the LORD has heard of your misery.
He will be a wild donkey of a man; his hand will be against everyone and everyone’s hand against him, and he will live in hostility toward all his brothers.”
Genesis 16, a better description of Islam cannot be found.