What's ur opinion? : the quarrel between israel and arab began from sibling rivalry?

in old testament version, abraham's legal wife was sarah and his son and heir was isaac, while with his slave, hagar, he had a son named ishmael. sarah then expelled hagar and ishmael to the desert. but in koran (islam holy scripture) version, abraham's legal wife was hagar and his son and heir was ishmael. he lived with them in the arabian desert. i guess isaac became the forefather of israel, and ishmael became the forefather of the arab. see the connection? what do you think?