Islam is the state religion of Saudi Arabia. There is no law that requires all citizens to be Muslim, but non-Muslims and many foreign and Saudi Muslims whose beliefs are deemed not to conform with the government’s interpretation of Islam must practice their religion in private and are vulnerable to discrimination, harassment, detention, and, for foreigners, deportation.  Neither Saudi citizens nor guest workers have the right of freedom of religion. The dominant form of Islam in the kingdom—Wahhabism—arose in the central region of Najd, in the 18th century. Proponents call the movement "Salafism", and believe that its teachings purify the practice of Islam of innovations or practices that deviate from the seventh-century teachings of Muhammad and his companions. The Saudi government has often been viewed as an active oppressor of Shia Muslims because of the funding of the Wahhabi ideology which denounces the Shia faith. Prince Bandar bin Sultan, Saudi ambassador to the United States, stated: "The time is not far off in the Middle East when it will be literally 'God help the Shia'. More than a billion Sunnis have simply had enough of them."