In Islam, the first of the five pillars is the shahada. Shahada is the Muslim profession of faith, expressing the two simple, fundamental beliefs that make one a Muslim: La ilaha illa Allah wa-Muhammad rasul Allah. There is no god but God and Muhammad is the prophet of Allah. Sincere recitation of this confession of faith before of two Muslims is the sole requirement for those who wish to join the Muslim community. It represents acceptance not only of Allah and his prophet, but of the entirety of Islam. As one of the Pillars, the shahada must be recited correctly aloud with full understanding and internal assent at least once in every Muslim's lifetime.

The shahada is also recited in the muzzein's call to prayer, included in the salat (daily ritual prayer) and incorporated in Sufi contemplative prayer. It is also recited in the moments before death. From the shahada are derived the other fundamental doctrines of Islam: angels, the Quran and the Bible, the prophets, and the Day of Judgment.