Because Ishmael was the first son of Abraham and the Arabs share a lot of history with the Jews, they are Abrahamic traditions. In the apocryphal Book of Adam and Eve, Ishmael and Isaac seem to be a little friendlier than in the Bible where Arabia or parts of it are mentioned many times. Islam borrows from Judaism in many practices and acknowledges the same God while managing to be heretical to both Judaism and Christianity. People forget, or never noticed, that there was ancient traffic between the Hebrews and the Arabs. There was even a dynasty of Jewish kings in Arabia. It ended shortly before Mohammed and lasting bitterness may have had something to do with his opinions about Jews. Fun history: when the Khazars were asked (i.e. pressured by the world superpowers of the time) to choose either Christianity or Islam, supposedly they asked the Muslim envoy which religion was the more original and close to the truth, Judaism or Christianity. He said it was Judaism. When the Christian envoy was also asked which was more basic, Judaism or Islam, he had to make the same answer. So the Khazars became Jews.