WASHINGTON - When a believing Muslim is summoned to the United States due to life's circumstances, Saudi Arabian authorities disseminate through a network of major American mosques, like other religious directives, clear ways as to how one should act in his new surroundings. Take, for example, a document signed by the cultural attache at the Saudi embassy in Washington that instructs Muslims arriving in the United States not to initiate a greeting when meeting Christians or Jews, and never to convey good wishes marking a Christian or Jewish holiday. In general, the attache recommends that the Muslim believer avoid friendships...