To add, the Torah apparently permits Jews to loan money with interest to Gentiles, but not to fellow Jews. So a disproportionate number of the Jewish diaspora eventually became urbanites centred on finance and specialized crafts.
The Torah obligates Jews To be HOLY. That means “set apart”. The distinctive thing about Jews is distinction itself. G-d instructs Israel “to make a distinction between the holy and the profane”, between that which may be eaten and that which may not be eaten, and yes, between Am Yisroel (the people of Israel) and the nations. This isolation, necessary for the creation and continuity of the fledgling Torah Culture, was a double edged sword: it protected Israel from the surrounding pagan cultures, and provoked resentment, fear and hatred as it demonstrated its superiority over them. Nothing has changed. Western Civilization, which has inherited Torah true concepts through the Christian stream is the dominant force of world history. We now have a president who denies this truth. And by course, Liberals, in their feckless attempts to ameliorate the demonic hate of Islam, follow in this absurd denial. I am sorry to add that many Jews are among them. These are self-hating Jews, at war with their true selves, their G-d and his Torah.
Not true. Jews were not allowed to associate with Gentiles.