Originally Posted by Plechazunga

They have common ancestors. Arabic and Hebrew are are on different sub-branches of the same branch of the Semitic language family.

Genetically, Arabs and Jews are closely related according to the tests that have been done, but it's complicated... the Jews whose ancestors lived in Europe the last 2000 years or so have mixed with a klot of other ethnic groups, and likewise the Arabs have mixed with Turks, Kurds, Persians, Europeans etc. Then there are the Jews who stayed in Palestine and other middle-eastern countries, who have mixed with Arabs - they are obviously closer genetically, I assume, but I've not seen specific results on that.

http://news.bbc.co.uk/1/hi/sci/tech/742430.stm