The Shahada is the creed of Islam. The Arabic creed translates to: “There is no god but Allah, and Muhammad is his messenger.” The Shahada is divided into two parts: the first—“There is no god but Allah”—is a confession of tawhid, the oneness of God upon which all Islamic theology is based. The second—“Muhammad is [God’s] messenger”—confesses the belief in the prophethood of Muhammad, from which comes Islam’s complete ethical code. Shi’a Muslims often add “Ali is the vicegerent of God” as a third confession, which Sunnis condemn as a fabricated addition. The full text of the Shahada does not appear in the Qur’an, but can be found in various hadiths.
Muslims consider reciting the Shahada to be the first and most important of the Five Pillars of Islam, since understanding and accepting it means that one understands and accepts the essence of the entire faith. In fact, Muslims hold that belief in the content of the Shahada is the foremost distinguishing characteristic that defines a Muslim as a Muslim. A single earnest public recitation of the Shahada in its original Arabic is all that is required to convert to Islam. The difference between the Sunni and Shi’a Shahadas, with Shi’as adding a confession that Ali is God’s vicegerent, is a significant source of theological tension between the denominations, given the importance of the Shahada to the faith.