From wikipeadia
Islam is the state religion of Saudi Arabia. The connection between Islam and Saudi Arabia (or at least the western Hejaz region of the country) is uniquely strong. The kingdom, which sometimes is called the "home of Islam", is the location of the cities of Mecca and Medina, where Muhammad, the messenger of the Islamic faith, lived and died, and attracts millions of Muslim Hajj pilgrims annually, and thousands of clerics and students who come from across the Muslim world to study. The official title of the King of Saudi Arabia is "Custodian of the Two Holy Mosques"—the two being Al-Masjid al-Haram in Mecca and Al-Masjid al-Nabawi in Medina—which are considered the holiest in Islam.
Saudi Arabia is the birthplace of the Arabic language, the language of the Quran, the central religious text of Islam. It is unique among modern Muslim states in being the only one to have been created by jihad, the only one to claim the Quran as its constitution, and unique among Arab-Muslim countries in being the only one to have escaped European imperialism. The country is also noted for its conservative official interpretation of Islam, which has influence well beyond its borders, thanks in large part to the country's largess towards Islamic causes funded by its oil exports since 1970s.
In the 18th century, a pact between Islamic preacher Muhammad ibn Abd al-Wahhab and a regional emir, Muhammad bin Saud, brought a fiercely puritanical strain of Sunni Islam first to the Najd region and then to the Arabian Peninsula. Referred to by supporters as "Salafism" and by others as "Wahhabism", this interpretation of Islam became the state religion and interpretation of Islam espoused by Muhammad bin Saud and his successors (the Al Saud family), who eventually created the modern kingdom of Saudi Arabia in 1932. The Saudi government has spent tens of billions of dollars of its petroleum export revenue throughout the Islamic world and elsewhere on building mosques, publishing books, giving scholarships and fellowships,[4] hosting international Islamic organisations, and promoting its form of Islam, sometimes referred to as "petro-Islam".
A conservative prescriptive and literal interpretation must be a convenient way for the Saudi Royal family to control the masses. It's not about spirituality, it's about control and power.