An ethnic group and a religious group are two very different things. Ethnic groups share culture, language, location, ancestry, etc. Some major ethnic groups in the Middle East are Arabs, Persians, and Kurds. Not all people in an ethnic group have the same religion. However, religious groups share the same beliefs in god(s). For example you could have Arabs who are Jews,Muslims, and Christians but are still in the same ethnic group. Though both groups are pretty similar they have some differences, too.